5 might seem legit for small traffic sites, but I think for Stack Overflow it should be raised.
Recently I had a question closed and reopened (without me editing it to make it reopenable) and I had a Q closed where 2/5 votes came from people who gave answers and in comments I told them that one of them was not good because it was too general, and other one was just wrong IMAO.
So is there a reason why 5 was selected, and shouldn't people who submit an answer to a question be blacklisted from voting for closing (to prevent hurt feelings close votes (in general, I'm sure this wasn't the case in my case)).