Is this behavior considered as spam or is permitted to create such topics?
Yes, it's definitely "SPAM".
but I noticed many accounts do that.
Report those accounts as well...
I have reported some topics, but I do not report much,
so I do not know if posts have been deleted or not.
- Save the links to those topics/post and revisit them from time to time.
- Check "
Deletion/Mod log"