Non-native speakers I can make allowances for, but ... a the same time ... the long-term impact is the same.
But ... the vast majority of what I read on here is written by native 'American' English speakers. ... and it is a linguistically impoverished creole barely more sophisticated than a pidgin.
It facilitates communication between native speakers of differing languages ... but at the cost of debasing the language — and debased language leads to debased thought.
I used to be on Facebook a long time ago ... had a DJ profile and everything. I communicated with people from all around the World as a result. It did not impact my own grasp of the language in any way.
It's not the non-native speakers who are the problem, it's the 'Americans'.