They can't but they should imo.
Status effects that appears on the cards can't be removed by locking the unit but I believe it's a mistake from CDPR.
There is two problems with that, first, and your topic kinda shows that in a way, it's extremely confusing for players. You explain that lock remove a card effect but wait, not those ones...Sorry but it makes the game unecessarily convoluted.
Second, it makes controlling more and more of a pain. Before purify was a thing, you could put a lock and be okay with every cards that have an effect and it was not broken because you have so many locks and not every decks were playing lock targets anyway.
Now locks don't even worth it anymore since they only solve a couple issues at best...And as a matter of fact, purify isn't that great either because they answer only a few things too (I mean, they're still better than lock atm due to Defenders but in the grand scheme of things, it remains a tech effect that will provide an acceptable value in only a few situations).
I feel like they put too many different options to deal with situational effects which makes the game a lot more tedious to play.
Don't get me wrong, I still love Gwent but I feel like making so many different effects that are dealt with in so many different ways deteriorate the experience a little bit.