Okay, to get one thing out of the way first, I get it; people aren't fond of DRM, and I'm not necessarily here to discuss DRM, at least in terms of file encryption and inconvenient always-online setups. I'm more so just looking for advice on how to go about the whole situation.

1. Does the itch.io staff take any sort of active measures in taking down illegal offsite downloads? I'm not asking for them to constantly scour the internet to make sure nobody's uploaded a copy of my game without permission, but if I find an upload somewhere that violates copyright laws, is there anyone on here I can contact for help getting them taken down? Or do I just have to rely on the provider of the service it's hosted on?

2. What makes people want to support a game versus taking the path of least resistance? Two kind of conflicting arguments I've heard are that a game people aren't willing to pay for isn't worth buying, and that every game in existence has been and will be pirated. Unless no game ever created has ever been or ever will be worth buying, it's pretty obvious that there's a right way and a wrong way to go about publishing a quality product.

3. If I did decide to publish on Steam instead for the sake of DRM, would its relatively lightweight Game Maker DRM even realistically make up for the $100 greenlight entry fee and the 30% commission on each sale? It'd make pirating my game a bit harder than just downloading it and reuploading to Dropbox, but theoretically, once that one illegal file is out there, whatever effect it'd have on my sales will be basically unavoidable, right?

4. What should I do if (probably more like when) it does happen? How much effort is it actually worth expending to squash every illegal upload, and how would I even go about doing it? Should I seek additional support if I think piracy is hurting me significantly, or is it a better idea to not call attention to the existence and accessibility of pirated copies in the first place? Is it a problem that gets better, or worse, the more you fight back?

To answer your first question, we make a point of taking down games that people upload to Itch.io without permission, but policing the rest of the Internet is simply not feasible. You must talk to the people in charge of wherever a pirate copy of your game was uploaded.

The other issues you raise being more subjective, I won't say much. Just that Steam DRM was cracked long ago, while Itch never had any, yet plenty of creators sell their games just fine. People pay when they want to support you, not when they're forced to. In fact, force them and they'll quickly decide they don't really need to play your game. Would you rather have your game played by pirates, or nobody at all?

One thing to remember is that most people who pirate your game probably wouldn't have paid for it if that was their only option. Often times it's kids/teenagers who don't have much money anyway. Obviously AAA publishers feel that DRM increases sales to some extent, since they pay a lot of money to implement it, but for indie developers I think you're better off putting more time/money into marketing. Launching on Steam might be worth it for other reasons (discoverability on Itch.io is very low) but the DRM shouldn't be a big factor (besides as NTTP said Steam games can be pirated too).

I'm trying to raise awareness of people about why piracy is a crime and how it affects not only game developers/content makers, but global economy overall.

How is my progress about this?
I got a lot of random rants everywhere.

But I won't give up so soon. I'll change this world! Everyone, follow me!! o/

About your question:
DRMs always get cracked, sooner or later. It's better to build an audience and try to conscientize your fans about how hard you work on your games and how you need to get revenue to keep doing your nice work.