Why choose 'bug feature-request discussion support' for tag when I see other tags like 'search' , 'not-a-question' etc? is this related to how many points one has?
No, this is not related to reputation at all.
To post something on Meta, you must have ONE of those tags.
The other 4 tags can be any other tag you wish, but you must at least have one of those tags.
This is to help with sorting posts. Chances are if your post doesn't fit into one of those categories, it doesn't fit into Meta.