If someone posted a text wall in one of our RPs, we would do two things. 
First we'd tell them to fix that.
Second we'd copy the post to a doc and break it up every three sentences or so. Then we'd read it.

If their posts regularly lack a basic level of grammar as well, we'd question their presence in our rp. But we'd also consider what they achieved in said post(s). More often than not, lacking grammar + text wall also comes with a side order of either doing very little or godmodding/metagaming or such.

Granted Mary Sue characters may make such, but we don't let those in through our strict CS approval process. We've found that being strict on CS reviews avoids most post issues. Not all, of course.