I'm okay with ROMs of games that don't help out developers in any way.
It would be erroneous to assume that these sales don't help out developers in any way. If a game can remain profitable for 30 years after its release, that raises the value of gaming IP in general, which is good for developers. If you're making a game today, it will be worth more to a publisher who thinks nostalgic old farts will still pay to play it many years from now than to a publisher who thinks it will be forgotten by Christmas.
Buying CD's from the major record companys hardly helps your favorite artists, over 75% of the money goes to big wigs, not the awesome guys (and girls!) putting their life into their content.
Sure it helps out your favorite artists. These label deals are mutually beneficial - if they weren't, the artists wouldn't agree to them. But the only reason the record companies bother with the investment is because they think they will get lots of profits from CD sales and whatnot. So yeah, buying CDs encourages deals that benefit your favorite artists.
However, with the latter, I get deeply annoyed if something I could pick up essentially free due to being abandonware suddenly requires payment of £10 for the pleasure.
It's fine to criticize something you think is overpriced, but using "free" as a baseline price is rather unfair.
My policy is that I'm fine with ROMs of games no longer available, but you have to pay if they become available. But if you do own the game in some legal form, I think it's just fine to continue playing them in ROM form, which is often preferable to "legal" forms.