You're wrong, and I've already given examples throughout this thread. Find them.

Well, as a novelist, knowing how to make bombs could be very important for a book. Or maybe you're just curious. Or maybe you're wondering how bombs work. Or you could have a school report. Or maybe you're interested in fireworks and rocket ships (which are, essentially, bombs) or controlled demolition. Maybe you think the apocalypse is coming and you want to be prepared to fight the zombies with bombs made out of stuff you found in the ransacked supermarket.

Does it matter? I know how to make bombs (go high school physics!) but it's not like I'm going to bomb city hall. I know how to snort coke (and so do you! Everyone knows how to snort coke) should I be arrested for future snorting of coke just because I know how?

Measuring performance is pretty much the job of managers (principals, in this case), and is difficult in every industry. That being said, some teachers are really, really obviously bad teachers that need to be fired (screaming at the class, throwing chairs at students, and teaching incorrect "facts" [like Mars being the smallest planet in the solar system]), but can't be fired because of union regulations.

"Importance of subject matter" isn't 100% opinion based (can't do most subjects without a good math, English, and science foundations), but this can also be rarity of teachers teaching a certain position. If there's a billion people teaching English, lower pay, if there's four people teaching music, higher pay.

That's actually not true. Unions in other industries inspire fierce, fierce loyalty. You ever talk to a longshoreman? Or a miner? They love the union. Pretty much any manufacturing union as well, or any job with low pay and high danger, specifically because they know that, without the union, they'd be dead or maimed inside a week. If Foxconn employers unionized (if, you know, they wouldn't get thrown in jail for 5 years for doing so), they'd love the union, too.

Teachers, even when the unions are negotiating a better contract for them, pretty much always hate the union. They might actually be unique in this; I have not heard of any unions more hated by their own members than the teachers' unions.

That's typically not the complaint against teachers' unions (teachers should definitely be getting paid more). But that's independent from whether the teachers' unions are good or bad for teachers.

The complaint against teachers' unions is that they make it impossible to fire bad teachers. Pay and raises are based on the unions' bargained amount and not on a teacher's performance or importance of subject matter. And they actively lobby to increase the amount of standardized testing, which is useless. Further, most teachers hate the union, so you have a union composed of members that hate the union. How does that even make sense?

Legal definitions for injury aren't based off the relative strengths of the perpetrators, but on the injury caused. Also, when is it "okay" for a three year old to hit and kick an adult man as hard as possible?

That in mind, a three year old kicking an adult man as hard as possible typically does not result in an injury greater than a bruise, and it would probably be possible for the victim to sue the child's parent in small claims court if an actual injured was incurred. Similarly, if an adult man, say, slapped a three year old (comparatively similar non-injury), the child's parents could probably sue the adult man in small claims court.

So, yes, they are the same.

I can only speak on my experience with teachers' unions in Washington state, but yes they can. A teacher in WA automatically becomes an "agency fee" member of the teachers' union, must pay dues to the union, must accept the union's collectively bargained salary and benefits packages, and must go on strike when the union says to go on strike. If they become a full member (for a higher due) they get some additional benefits (liability insurance, representation, voting in the union, etc.). But as far as salary and basic benefits bargaining, they get what the union gets. So even if you're "not a part of the union," you're a part of the union.

Aside: teachers' strikes are... weird. Because of how their pay is setup, they keep getting paid and, often, will end up working the same number of days just pushed into summer. Since the public schools aren't making something to sell, they don't have much of an incentive to get the teachers back to work (no lost profits). And the youth crime rate spikes because all the hooligans don't have school and get bored.

(Apparently I'm not the only one who hates teachers' unions.)

I've been reading more into this case, and it looks like there wasn't any actual salary fixing or hiring bans. Essentially, the companies agreed to not "cold call" each others' employees with job offers, and this may have affected the salaries of some number of employees who would have been able to negotiate better salaries. But, let's be honest now, cold calling another company's employees is kind of a dick move.

So, essentially, they're being hit with an antitrust case for agreeing to not be dicks to each other.

And we wonder why capitalism results in the biggest dicks coming out on top...