I think you're looking for this:
https://slashdot.org/my/commen...

In your slashbox, click the Account link.
That takes you to a Preferences page.
Click the Discussions link at the bottom:
https://slashdot.org/my/commen...

It isn't documented any where and I can't recall where I first learned of it because it was years ago but you can get TLS on Slashdot.
Subscribe.
Once subscribed and logged in it should transition you to TLS, at least it does for me.
If it does not you can force the matter with Noscript.

Off hand has anyone noticed Noscript unblocking Google analytics and other domains and certain other analytics domains with each new update?

I also use the Calomel TLS grading extension for Firefox.
Slashdot has been graded Red for years. Dice just upgraded the cert a couple of days ago and it is now graded Blue with PFS. Not Green but at least it's not Red anymore.

Please google OSI and look into "Open Source" that's a capital O and a capital S!
Please also google FSF and look into "Free Software".
Again a capital F and a capital S.
The capitals !@#$@!# matter!
Public Domain does not == Open Source, There is no such thing as open source.
Or are you just trolling!?

Public Domain is public domain. Copyright has expired or been forfeit in order to put it, what ever it is, into the public domain.
With Free Software and Open Source software someone holds the attribution to the rights of the work.

You are correct that they do not come right out and say that in the faq. I'm not sure if they did in the past.
However in the FAQ at:
https://slashdot.org/faq
At section Subscriptions with question:
Why subscribe to Slashdot? Can't I read for free?
You find the link:
https://slashdot.org/faq#subsc...
That takes you further down the page with more details where as you said it does not mention this.
*It is an unmentioned plum.*

While you are logged into your account observe on the upper right where I expect you have your Slashbox.
If you don't then go enable it.
With that enabled you have the default content that goes in your Slashbox and it lists your current Karma.
Mine has been Bad since I think about 2007. Haven't seen a mod point sense.
Below Karma you have three links:
Journal Subscription Account

Subscription is this link:
https://slashdot.org/subscribe...

Where in you read:
Absolutely nothing about this!?
Hrm. I could have sworn I read about this and didn't just figure it out on my own.

Okay they either covered this before and removed it. Not sure and don't know why they would do that.
Or I read this in a post several years ago and just assumed everyone I've been reading complain about this just didn't want to subscribe.
I subscribed a few years ago and wanted encryption and also had trouble with this feature due to redirects.
I resolved this by putting
*slashdot.org*
in my forced HTTPS NoScript settings and then added
slashdot.org/my/login
into the whitelist for the never force https list.
Anytime my session/cookie expires I put in slashdot.org/my/login and then get redirected to a https slashdot url.
Hope that helps you and many others and that they don't degrade this for some reason!?

They want you to pay to use https.
If you subscribe and login you can browse with https urls for as long as your session cookie is remembered/hasn't expired.

Not standardized from what I can see but work has been done to allow this:
https://encrypted.google.com/#...

Not positive this would resolve the issue but maybe a iframe with sandbox parameters as applicable. I think I've read you can do this. Not sure though.

Bad side effects: Forces DNT:1 header regardless of firefox preferences set.
Examine ip-check.info to know why this would matter.

window.name

Window Name Eraser for chrome.
Nothing for Firefox as yet.

Tracking can be done via more than 3rd party cookies.
Whether you use TOR or not please check out:
http://ip-check.info/

Certificate Watch

Two feet tall.