There is a large ripoffs section on TER where all the bad providers are listed with lots of reviews backing up. my question is why is it that so many go to these providers and review them?? shouldn't the first two or three reviews prevent people from calling and trying the meet these providers?

This happens from people not doing their homework despite that they're TER members.

Some guys just think it will not be the same for them.  They are this handsome hunk and the girl will perform for them.  Don't kid yourself.

Do your homework and you will not be disappointed.

A lot of non-members join TER after being ripped off, scammed, upsold, B&S, etc.  To be honest, I did.  Others think the "get VIP" is a hussle...  when it's really a necessary tool and far cheaper than even one spoiled date.  
It's not just the rip offs either...  One really needs to read the full reviews.  I do not disqualify a potential date for a single low review on a page...  but I look for what went wrong.  I always read the full page & often the details will reveal something minor which will decide Yes or No.
There is no replacement for learning how to do this right.
skb

You just asked the Million Dollar Question!

The answer is that all those guys who write subsequent reviews went to see the lady BEFORE they checked her reviews, then they had a crappy experience and wanted to vent about it, and only then did they discover that she already has a long list of bad reviews. Hopefully they learned their lesson from that and made it their habit to check for reviews first.

Some guys do not check reviews until after the fact.  Others are ever hopeful.  They hang on to the hope that "against all odds" something different will happen and they will have a great experience.