The term I was thinking of is "knock-off artists."

I don't like what they do. It's ok to take an existing idea and adapt it. E.g. to try to make a web-based version of a desktop app. But there is something contemptible about copying something so literally that you even copy the mistakes.

It does smell a bit funny, but in a way what they do is not just copy an app but rather create an international / European knock-off. They identified a weakness in the way American startups operate - concentrating on the American and/or English-speaking market for very long while neglecting the rest of the world, and they're taking advantage of that. Their business model would become obsolete if startups became better at addressing international markets.

For what it's worth, I'm a native English speaker and wondered the same things.

Copycat is the most unambiguous word I can think of.