[mrwyz]

Only if you think taking the work of others and profiting from it without contributing anything back is fine.

[g15jv2dp]

The people who did the work obviously think it's fine, otherwise they wouldn't have licensed it under such a permissive licence.

[mrwyz]

Certainly. MIT/BSD more or less says: steal away (but retain this license notice). In some cases that's desirable.

[bigstrat2003]

I am not going to debate whether it's "fine", but it's certainly not stealing. If I make someone a beautiful necklace and they sell it in an auction, I might wish they hadn't done that with my gift - but they haven't stolen anything either.