Having been around MAME and the various boards for well over a decade, I really don't know that the hate towards him is that justified anymore. Back in the day he definitely did some things that really came off as "neener neener, look what I have, uh uh, you can't have it" but it really doesn't seem like that anymore all things considered, and that everyone is just pissed that he doesn't feel automatically compelled to share everything like others do.
I mean, it's great that we have so many people willing to do the work and time and money invested to give it to MAME which ultimately gives it to "everyone" and I wish a lot of people actually appreciated them more at times, but I think people have gotten spoiled by those efforts and assume that anyone else automatically has to be as generous.
Honestly these days I'm more interested in reading about the efforts made to emulate the game and perusing the source code than actually playing anything in MAME, I think I have the same 25 roms that I've had on here for about 9 years. The last 5 years have held a lot of things I've had interest in watching develop, without any interest in playing them (the main exception being the slew of Sega games after the encryption breakthrough which I ran and played a bunch of at the time for the novelty and "oh man, they finally did it!").
I guess all my rambling is saying is that the only thing I wish that safestuff did differently is that it would be nice if there was a way he could contribute to the emulation for some of his coveted (unique, one-off, proto and such) games in some way that wasn't going to automatically release everything to the wild and devalue his collection, either monetarily or uniqueness-wise, which I'm sure is his main concern aside from the other things always mentioned. Mainly because preserving the ROMs is only really one step of preserving the games in the MAME sense, and the documentation is the aspect I enjoy the most, and we've all seen how well emulation progresses on "randomly strewn dumps from some unknown unique system of some type with no documentation" games. Yeah, efforts can and will be made through hard work but it's arduous and some things may never be more than guesswork. I know he's done stuff here and there like that though, which is also good, and if people are just getting upset because he has some random prototype version of a game that already exists in mame and doesn't differ that significantly (and especially if he's actually providing tech info and pics on it if requested), and they just gotta catch em all, well. Pffft.
I think that would involve a level of trust that he might not have on things leaking themselves, and honestly, if there was, say, a fully-functional-if-only-someone-had-the-roms marble madness 2 driver in mame, the moaning would probably increase a hundredfold because SOMEONE MUST HAVE THEM PLZZZZZZ.
Besides, yes, even if it does seem like everything he finds is disappearing into a black hole emulation-wise, it still exists which is more than could be said if it ended up in the trash or destroyed in some way. Someday he could potentially change his decision, and at the very least, we know a copy exists and where it is. Unless he's actually swooping in and getting into bidding battles with MAME-friendly people or otherwise snatching them out of their hands in some way (which yes, I think he may have done a few times back in the day?) we really shouldn't look at everything he gets as somehow stealing it from MAME. Sure, be jealous that he's a lucky bastard with a bunch of cool stuff. I've done that. Now if he is still (literally, not just by owning it) taunting people with his collection and I just haven't seen it, I take some of that back, or even if he's willingly holding back things that could genuinely help MAME for no reason other than he can* (and I do count "devaluing his collection" as a reason, even if it's a bad one), it's just that all I ever see lately is he posts some stuff he got and then EMURAGE.
(*For instance something like:
Dev: I really need to find someone with the Rev A Tower of Ninjas so I can compare the data on the J2 chips, but it seems like they've all been converted to Rev B. Let me post on various forums asking about this.
Safestuff: Hi MAME dev, I have Rev A right here in my garage! I actually found it in the middle of a grassy field one day when I was walking my dog.
Dev: Oh, great! can you dump J2 and send it to me so I can compare it with the dump we have?
Dev: Uh...ok. Well, can you at least tell me if-
Safestuff: I just felt like pointing out that I owned one, that's all.)
If these conversations are happening on a regular basis and I don't know about them, then I guess I can understand the wrath.