Pretty much I think that is FUD. Since everyone else can withdraw. this threads made me try myself withdrawing. So their FUD works btw.
In general, traffic on poloniex grow exponentially right now there is 32k people online trading. Poloniex keep employing new people last year, but for sure could not train and employ enough on time. So when peoples withdrawal and deposits from different reasons went wrong it takes way more time to resolve them. Everyone knows best for them self what they do wrong.
Oh and OP Monero markets are here:
https://coinmarketcap.com/currencies/monero/#marketsBut avoid BitFinex and HitBTC since they dont have withdrawals. LOL seems that is a popular thing now in Crypto exchanging.