hey mozilla how is your legal department so bad that you start your acceptable use policy with "follow all laws" and about halfway down there's "don't harass people" and everything else in there is something that sounds close to a law but is misworded in such a way that it basically makes all online communication illegal

Let's go through these with some examples for each:

Do anything illegal or otherwise violate applicable law,

So the second half of this is almost sensible. Mozilla doesn't want to be blamed if you use their software to break an applicable law.

But the first half being included in addition to that means that not only are applicable laws considered, but all laws. If something is illegal in one town with an unpronounceable name nobody has ever even attempted to say, you can't do it with Firefox.

The second one is the opposite; it starts sensible and then veers off wildly to mean something ridiculous:

Threaten, harass, or violate the privacy rights of others; send unsolicited communications; or intercept, monitor, or modify communications not intended for you,

The part before the first semicolon? Sure.

The part after it? All of these violate this term:

emailing someone and not having that email be a reply
moderating a forum
working as an editor for a book or a blog post for which you are not the target audience
receiving an email from someone who typed your email address by mistake

Third one is also almost sensible. The problem here is "users".

Harm users such as by using viruses, spyware or malware, worms, trojan horses, time bombs or any other such malicious codes or instructions,

Now, they could have left this out, because surely there's some place on Earth where it's illegal to intentionally give someone a computer virus.

But the inclusion of the word "users" means that this specific rule allows you to give anyone a virus as long as they do not use a Mozilla service.

Fourth one has a problem specifically in the first two words:

Deceive, mislead, defraud, phish, or commit or attempt to commit identity theft,

Since all of these comma-separated items are independent, they're saying you can't do anything that is deceptive or cause people to be mislead, regardless of your intent.

If you type a pun, you are violating this term.

If you pretend to not know what you're getting someone for their birthday even though you already decided, you are violating this term.

If you are a magician or a comedian, you are constantly violating this term.

Engage in or promote illegal gambling,

This is the fifth bullet point, and taken in conjunction with the first bullet point, this means that you are not allowed to promote or do illegal gambling, but specifically the kind of illegal gambling that doesn't break any laws.

Degrade, intimidate, incite violence against, or encourage prejudicial action against someone or a group based on age, gender, race, ethnicity, national origin, religion, sexual orientation, disability, geographic location or other protected category,

The sixth bullet point is the one I can't find any fault in, except maybe that it applies the same level of importance and badness to being homophobic and to saying "what are you, five?" casually in a conversation.

Exploit or harm children,

Again, illegal things are already disallowed, so this only adds legal ways of exploiting and harming children to the list, like selling their personal information that you collected as their trusted browser.

Sell, purchase, or advertise illegal or controlled products or services,

The eighth bullet point completely misunderstands what a controlled substance is.

If I get an email from a pharmacy saying that the prescription for the medicine I take for autism has been filled, that email is about the purchase of a controlled substance.

Controlled substances are not illegal. They are controlled. You can figure this out by context clues from the way they felt the need to say "illegal OR controlled".

Upload, download, transmit, display, or grant access to content that includes graphic depictions of sexuality or violence,

If I watch a video of Counter-Strike, that violates this term.

And importantly, it says sexuality. So it's not just porn. Pride flags would also count. They depict sexualities in a graphic (relating to visual art) way.

Collect or harvest personally identifiable information without permission. This includes, but is not limited to, account names and email addresses,

If you found this post and read the two lines at the top that tell you who it's from, you are violating the Firefox terms of use.

Engage in any activity that interferes with or disrupts Mozilla’s services or products (or the servers and networks which are connected to Mozilla’s services),

Okay, a bit weird to have this after "all things that are illegal anywhere" and "any computer attack", but I guess mozilla wanted to be extra sure just in case their services at some point no longer run on computers

Violate the copyright, trademark, patent, or other intellectual property rights of others,

mickey mouse

WHAT I JUST DID WAS ILLEGAL

Violate any person’s rights of privacy or publicity,

I had to look up what "rights of publicity" are and it seems like it's just privacy rights but for famous people.

But none of that matters because the entire reason I'm reading this document in the first place is that Mozilla announced they will sell my personal data.

I sure hope nobody there uses Firefox or someone's gonna get real angry.