This happens all the time on UA.
Wonder why they reacted so strictly as I sat next to quite a few pax who were
still on the cell when we were already entering the runway. And at least had
one seat neighbor who continued during take-off.

So either this was a specifically obnoxious and loud specimen or the harsh
action was induced by the foreign language in which case he can play the
race card...

Can a pax be banned from flying UA for a non-immediate safety violation?
I know that in Europe cellphone use is considered a crime against aircraft
integrity but how is that looked upon in the States?