A member would have to run up a lot of grammar errors over a very short time to be banned.
Any points accumulated for basic grammar errors run after 1 week. Any ban applied, for basic grammar rule violation is a temporary posting ban, so you can still read in the forum during that time, and any such ban is lifted after a week.
I have only seen a couple of members get such a ban - it is very rare, and unlikely to happen if you try your best to follow the rules, and ask questions / ask for help of you are struggling.
I know I've said this before, but the grammar rules are only in place for the benefit of everyone. If you write a post, you presumably want people to read it and reply. If your post is difficult to follow, has no full stops, is full of typo's, has lots of text speak that people don't understand, has only one enormous paragraph etc, etc, then people won't bother to read it. If people don't read, then they certainly don't reply. The rules are in place for your benefit. Some people say that they want to freely post their thoughts, without having to think about grammar. But if no one reads it, what's the point of writing it on a forum?
The notifications are to help you, not to punish you. All the notifications contain links so you can read and learn how this forum works. But there does have to be a limit, because staff can't spend hour upon hour editing posts. It is your responsibility to follow forum rules, and make your posts easy to read by following basic grammar rules.
Stop taking a reminder of forum rules as a personal attack - that is so not the case. All anyone wants (staff, members, visitors) is a forum that is easily accessible and easy to read (on all devices), no matter where in the world you live.