But who gives merits?
Are each other's alts doing this?
No.
Now, are large forum merit sources distributing these merits to these spammers? I have serious doubts.
Yes. Not sure why you'd have doubts about that - read 10-20 pages of WO and it's quite obvious.
Merit sources are not infallible. And perhaps in this case they believe that Bitcoin-bullish posts (even low-effort ones) deserve merits. It all comes down to this: "do I want to see more posts like this in this forum/thread/etc". I don't. I guess nutildah doesn't either. Users who send merit for those posts apparently do.
I don't think anyone's credibility is being questioned here. It's just a difference of opinions. And as one of the WO "regulars" explained to us peasants, our opinions don't matter anyway.