How come "Brexit" is used as an example of why to vote for Clinton?

I understand the lesson “be careful what you vote for”. The thing is, though: Brexit regret was expressed by those people who did not vote for the outcome they actually wanted. If anything, I can see Brexit teaching us two things:

1) Vote for what you really want. Yes, surprise, your vote does count.

2) Go vote!

What am I missing?

P.S.: I’d love for this thread to stay on-topic.