I suppose if you insist on viewing the proposition as one of logical implication, then yes, it would be a fallacy, because the arguement would effectively become "any time anyone does a bad thing, it means they're going to do a badder thing next" and I doubt that accords with most people's experience of the world.
Yes, I do insist on viewing the slippery slope fallacy by its defining characteristics. Like I said, a slippery slope is not just a sequence of negative events. There has to be a(n alleged) chain of implication. Here's an example of an argument that is not a slippery slope argument:
"My father's X-ray showed a lump on the prostate. Then, he'll find it painful to urinate. Then, he'll die."
This is not a slippery slope argument, because the statements do not follow on from each other (e.g. the pain signals from urination will not cause him to die). Instead, these follow from a single cause: that he has prostate cancer. Here's an example of a slippery slope argument:
"My father's X-ray showed a lump on the prostate. Then, he has cancer. Then, the cancer will spread to his brain or lungs. Then, this will cause him to die."
It seems reasonable, but due to the slippery nature of probabilities, it's a lot less solid than the sum of its parts.
In the case of the Pastor's lament, we have a master causes, like the cancer in the first argument, e.g. the Treaty of Versailles. Everything the Pastor said happened because of Germany's wounded pride, not because Germany hated the communists. So, in fact, the "archetypal" slippery slope, is not typically considered as a slippery slope.
That said, I genuinely believe you're the only person using the term in that way.
I did a critical thinking course at university, and this is exactly how it was presented to me. It's also exactly how I had perceived it previously. I can also back it up with Wikipedia:
The argument takes on one of various semantical forms:
* In the classical form, the arguer suggests that making a move in a particular direction starts something on a path down a "slippery slope". Having started down the metaphorical slope, it will continue to slide in the same direction (the arguer usually sees the direction as a negative direction, hence the "sliding downwards" metaphor).
* Modern usage includes a logically valid form, in which a minor action causes a significant impact through a long chain of logical relationships. Note that establishing this chain of logical implication (or quantifying the relevant probabilities) makes this form logically valid. The slippery slope argument remains a fallacy if such a chain is not established.
* Some claims lie in between the two. For example: "If we accept censorship on most disgusting material, the politicians may easily widen the area under censorship. This has happened often before too, with far-reaching consequences. Therefore, we should completely avoid the slippery slope of censorship." This claim is not a fallacy: some people think that there is enough evidence for the claim to be probably true, some not.
In all of these forms, notice that the "slope", or the chain of implication is always present.
But unless I didn't read far enough back up the thread, I don't think anyone is saying expanded censorship follows as a logical necessity of restricting Internet porn.
Perhaps, but really it's the argument I am attacking. People seem to find it very convincing, but I can't find any solid reason why it should be. I mean, the OP claimed that this story was a great example of a slippery slope related to censorship, but I see no reason to suggest that it was early censorship that caused this to happen, instead of common anti-pornography attitudes by people in the UK. That is, I doubt this is even a slippery slope.
It was an archetypal slippery slope. Start by disregarding the civil rights of one small and unpopular minority, and when you get away with that one, move on to larger and less unpopular one. Repeat until political aims are met.
That's more of a "boiling the frog" kind of argument. It is distinct from a slippery slope, because it requires something to be turning up the heat, whereas, in a slippery slope, the heat keeps rising unstoppably by itself.
In order to invoke that kind of argument in a sound way, you need to show that there is something turning up the heat. In this particular case, with the UK wanting to block internet pornography, we have, presumably, a puritan electorate. I would not expect them to push much further than blocking pornography, especially to the chilling extents that some people seem to believe it will be pushed to, given the chance.
I'm not saying that this isn't bad, that pornography should be banned, that people wouldn't miss it, or anything like that. I'm more demonstrating that these arguments against them should be taken with a grain of salt. If we were to, purely hypothetically, allow pornography to be blocked by default, I highly doubt it would intrude onto political speech, without some added unforeseen external factors. Pornography being opt in and the possibility of limited expansion of censorship is enough for me to oppose such a move wholeheartedly, without having to resort to hyperbole.
On the other hand you can't say "don't bother opposing Proposition X because people will oppose Proposition X and it all balances out". Because, of course, if everyone does as you suggest, then there will be no resistance to Proposition X and the measure will pass unopposed.
Of course. Like I said, it's about attacking arguments, not the cause. By all means, you can speak out. Just don't expect to convince me by painting as bleak picture as you can conceive of. I don't actually think the UK will actually block porn by default, so this is more of an exercise in critically evaluating arguments.