Indeed, translations are products of their times, and most casual readers are better served by (non-public domain) contemporary translations. I'm reminded me of something Mary Beard said in a recent interview with the LA Review of Books [1]:
"It's very interesting to look back at classics a hundred years ago. One of the things I've done is look back at Gilbert Murray’s translations of Euripides, which were huge popular success at the time. It seemed to engage with all sorts of political issues of the time. And you look at them now, and they're unreadable."
There certainly can be misguided or biased translations, but I routinely recommend old ones like the anonymous translations of Dumas and Hugo from the mid-19th c. and Pope's Homer. It's probably worth 2 minutes of research to make sure you didn't get a dud, though.
I remember when I did classical studies (studying the classics in translation) Our teacher commented that as she had been taught by nuns the version of Thucydides that she had read had all the "gay" stuff taken out.
Yeah, there's a gay aspect in the Count of Monte Cristo that got excised or downplayed as well. The question becomes do you want a biased translation that reads better or an unbiased one that reads okay? It's really a case by case thing. Any classicist will tell you Pope butchered the original Homer - he didn't even speak Greek. But his is still the best in English, I think.
"It's very interesting to look back at classics a hundred years ago. One of the things I've done is look back at Gilbert Murray’s translations of Euripides, which were huge popular success at the time. It seemed to engage with all sorts of political issues of the time. And you look at them now, and they're unreadable."
[1] - http://lareviewofbooks.org/essay/visit-mary-beard