The "relatively slow" 11 km/sec is still 39.600 km/h, or around Mach 30 (although that depends on air density and temperature), so still pretty fast I would say...
There's no authoritatively correct reference for what "slow" or "fast" should mean in extraterrestrial contexts, however, I think it makes sense to look at it like this:
Suppose you were watching a (CGI) movie or a video of a meteor hitting Earth, with the whole globe on screen.
The diameter of the Earth is almost 13,000 km. So a meteor(oid) going even 70 km/s is going to take 3 minutes to hit from one diameter away.
It should look like it's barely moving on a planetary scale.
The scale of things in astronomy is humbling to say the least. "Close" can be 1 light-year away... That's 9.4607e+12 km. "Slow" is Mach 30. We're nothing at that scale.
