Poloniex haters a simply a bunch of losers that had their first taste of how day trading is a losing proposition.  The trick is getting out before the dump.  Suddenly these idiots have found out how hard that is.  News Flash: When everyone else is dumping their shit coins, access to the system bogs down in order to do the same.  Let me guess what happened.  
     1. Joe Schmuck is in some shit coin scam like stellar or ripple.  
     2. Bottom begins to drop out.  
     3.  Joe tries to sell but with everyone else hitting poloniex it takes longer than normal as price falls.  
     4.  Joe chases the falling price until a sale order finally goes through.  
     5.  Woops, now there's a dead cat bounce and Joe's FOMO kicks in and he buys back in.  
     6.  Look out below, by the time he and everyone else realize it's a dead cat bounce, everyone begins chasing the fall again losing even more money.

That's not a problem with the trading platform, that's how being on the shitty end of day trading works.  Sucks to be you.