I'm sure this has been asked before but when I searched didn't see it.

So when Wes shoots at someone they lose their focus or evade.

Do they lose that before they get a chance to spend it or is it only after?

Which kind of seems pointless unless your running opportunist.

Had this happen last week where my opponent said it was after so we played it that way

It is indeed after the attack, which is after the full attack has been completed, damage dealt, etc.

Wes's ability doesn't do him much good, but it helps weaken his targets for later allies to take their shots. Think of him firing at a token-stacked Fel, or in cases where your opponent wouldn't have had to spend their token at all. He can also remove target locks, which can be really annoying for Bombers (or opposing Rebels).

I'm sure this has been asked before but when I searched didn't see it.

What did you search for? I just typed in "Janson Ability" into the little search bar at the top of the page and the first page of results had 5+ different threads that answered this question.

I typed Wes pilot ability and saw all kinds of different threads pop up

I always thought Wes ability removed the token before they had a chance to user it.

It does make his ability not as powerful.

Since he is going to strip it after the attack your opponent will user it anyway

He's also clearly explained in the FAQ:

"When a ship is defending against Wes Janson, it may use focus, evade, and target lock tokens during the attack. Wes Janson’s ability does not remove a token until after the attack has been fully resolved."

It is pretty useful when you strip away a blue target lock from them after you are done attacking them. Especially if it is a bomber who now loses its TL when it was about to shoot its missile or torpedo at another friendly during that combat round. So it is forced to use another TL action on the next round but now unable to use a focus action .

Or if a PTL Soontir had a second focus token when it already used his first focus for an attack or defense, you strip that away from him making him vulnerable from another attack from another friendly.

Wes's ability assists his other team mates even though it doesn't directly help him.