It is already tough for the ones who have no support to push them ahead, and the excessive amount of posts regarding this and the efforts of getting a Merit by creating threads in Meta has already proved that.
It would be too much to ask the genuine users to wait too long to rank up just one step. So it is much better to just keep demoting the one's who don't deserve to rank up and let the ones who deserve it keep going ahead.
Maybe you are right. The difference I see is that LoiceVs proposal depends on people actively accounts to demerit, whereas raising the requirement is automatic and works for everyone. It can be raised to 5 first. A newbie really interested in the forum shouldnt have problems to get those 5 merits, because people will qualify his posts taking into account that he is a newbie. Even theymos said that newbies should be merited for good posts, not exceptional ones.
Even though the amount of Merit required on each rank increased, there are still a lot of possible merit abuse out there and there will be more. Can you imagine giving 50 Merits to a garbge post? 50 Merits to a one liner posts? It's a total abuse. So deMerit is the best solution.
People who send 50 merits for one post get out of merits soon.
That guy probably got out of merits already. If he had sent 50, he would have been able to make just one account to rank up, instead of 48.