There's many other reasons as to why players are ST buffing an odd choice.

It can be because they macro'd it to not have to target.
It can be because they judge on another metric (gear, title).
It can be because it's their friend.

I wouldn't take that as people judging your DPS, I've seen dancer choosing a Samurai in poor gear rather than a full ilvl530 DPS.
Most people just go "Okay you get the buff because my mouse/macro decided so."