It's actually a practise. They do charge. I am not sure but i think the idea is to moderate the number of coins listed on the exchange. Though for maintenance I may tend to support. However, as regards listing, in my opinion it's absolutely wrong and ICO's are usually their target; thereby robbing the projects of investors money meant for execution. Quick regulation is needed in this area especially because such exchanges would continue to rake in Trade/Exchange income on that coin so long as it remains in existence.

Come to think of it, why don't they charge to list other mainstream coins like bitcoin, ethereum, etc. This is truly making the industry unhealthy and dragging it backwards. On the other hand, since STEEM is still traded on the subject exchanges, I am in no doubt disarmed by your findings and all I can say is that STEEM Inc needs to make the challenge know to steemians and the crypto space as it is now a community issue. On a final note the listing and maintenance charges urgently needs to come as a Topic on it's own and lets every crypto enthusiast help to steem, resteem, tweet and also Hash Tag it on every social media platform until it is addressed. Truth be told it's dragging the entire industry backwards. More like deliberate growth inhibition for most coins. I hope it's not a conspiracy.