in fact the chance is really high to loose if you do a lot of bets, even if you would get 50 losses in a row the chance to loose 51st will still be 50 per cent
That is not correct. One event does not depend on the other of course, but if you are talking about "in a row" then it depends.
I your example, after the 50 (and if you consider that as a "mark"), yes the % of losing the next one is of course 50%. But the chance of losing 50 in a row in 1M rolls is really close to 0% lol (you can't even get a result in the site
http://www.sportsbookreview.com/betting-tools/streak-calculator/)
He lost after 100K rolls meaning that the chance should be 1% (22 rolls in 100K, not the 50 in your example lol, that is almost 0), wich makes it a "rare" event, and he was quite unlucky. I won't say the site is rigged or anything like that, 1% is rare, but it happens. Of course that if that is happening to to many users then something is not correct.
But people should really pay attention to that, and not just say that is normal or wtv, and that martingale sucks (whitch is true, it sucks). That will just let the casinos do wtv they want because we accept everything.
Regarding martingale method - it is very hard to say - it is good or not. If people win,they say martingale is best, if they loose, they say martingale always loose. 
also withdrawing once you hit a set target is also a good idea as otherwise youll keep going thinking ur luck will never run out and when it does youll have lost much more than you bargained to 
talking from experience lol :O 
