As a german I can say this seems legit. I'd rather speak english to a non-native speaker than german, because most of the time it is hard to follow their speaking due to their faults in pronounciation and grammatics. Well, except when they speak german good (at least A2 or higher) or need it for their training.
I think a bit of both. English is definitely more flexible in terms of understandability as a second language for non-native english speakers. You can learn it relatively easy, unlike german (if you are not raised by german speaking folks). In the past we had a few TV programs that came unlocalized in german TV (Jackass, Beavis & Butthead, Celebrity Deathmatch). This exposed many of the younger people to english. The school system picked up english to the curriculum already in 1964. Back in my day (late 90s) we learned english since the 5th grade, today it seems to be third year primary school. Everyone learns english here, but too many people don't bother anymore after school and practically unlearn it.
That's really interesting. I've noticed quite a few German creators on YouTube and similar recently, there's a much bigger market for english language videos so it makes sense they'd target it. I wonder how this will affect language learning, likewise the other way around with so many viral videos being in English.