I think it's fine as long people know it's just for funsies. Like anything, there is always a line that shouldn't be crossed when things stop being just for fun and become serious or an obsession. It's just happens that in shipping culture crossing that line is super easy.
Personally when I was younger, I never understood shipping and thought it was cringey. However, I kinda get the fun of it now. I still don't get hardcore shippers thou.