For what it's worth, the user you linked to is paid. They're a developer at Stack Exchange, and used to be a community manager. Assuming you're talking about elected/appointed moderators, though:
Speaking for myself, I don't want to be paid. This is a fun, somewhat relaxing (sometimes terrifying) job, with no hours and relatively low expectations. I'm expected to give what time I feel comfortable giving to the site, to help the site.
Now let's say all moderators get a $10,000/yr salary (random number I pulled out of the air). Suddenly I'm being measured for pay. There's pressure on me to handle flags, because, ya know, it's my job. Also, we see (even more) candidates in moderator elections that don't want to do it because they want the site to prosper, but because there's money involved.
As a moderator, I wouldn't like the pressure. As a user, I wouldn't want to have moderators running a site I participate on because they want money. I want moderators that are doing it because they want the site to be the best place possible.
If you take away the volunteer part, you're left with hired hands that are out to make the numbers on the dashboard next to their name as high as possible.
User might be a spammer, but probably not? Meh, nuke them anyway. Because that adds to the number.
Someone posts something that's borderline, but you personally think should be left open? Close it, because there's a number for it.
I don't want to see this behavior. I don't want to exhibit this behavior. A cool hat and a couple t-shirts is plenty.