Since nitrogensports is being accuse lately same as sportsbetting the only remaining sports betting site that can be trusted these days are both
onehash and
BetBTC.
There's no problem in using nitrogensports they still have a high rating and their support already gave a response on the accusations.
I agree on this one not because i’m part of tha campaign but looking at their site fundamentally you can be more confident to bet on this site. Well, its good to have a more secured site when it comes to sports betting than to say sorry latet on with the wrong site.
777Coin doesn't even have sports betting and secure bitcoin sportsbooks does exist but saying it's secure doesn't mean they're not prone to getting hacked.
Just because the mentioned site are US esport gambling site doesn't make them the best available site now as you said even if they are I will recommend a site that doesn't have any ANN or representative on this forum if I were you because every esport site get bad reputation at some point and won't be a means to make any report if site don't belong to this forum.
If they don't have a bitcointalk thread there are other platforms where complaints can be handled(askgamblers,reddit,etc).