Fellow musicians, please help me understand the difference!

I always learned that vibrato should be limited to solo playing or small ensembles.

I know in a wind ensemble or orchestral setting players should blend their sound and avoid using vibrato as it detracts from the overall resonance that is possible by playing full, rich tones.

However, why is it proper for strings to add vibrato to each and every single note? I've never quite understood this. There is no way a whole section of strings would be able to time the frequencies of their vibrato at the same time.

I realize this is a dumb question, but as a trumpet player who is becoming increasingly interested in orchestra, I need to know!