Honestly, I also believe site manipulate games. I have some experience and between real life casinos and online the difference in horrendous runs ( pro casino ) really is staggering. Never had I ever lost more than 8 or 10 BJ hands in a row in a real casino, at stake once I lost 15 in a row and 21 of 23 ( plus some draws ) . Sure it might be "unlucky" but at stake at their originals I have never had a winning session , win/lose wise, if the session had more than 100 deals or throws.
The sites usually advertise with "Provably fair". This allows you to understand the game and the outcome, why you won or lost. Have you recalculated this in these cases or had it recalculated using online tools?
Or do you think that this evaluation option is already manipulated? I play very few games of chance on such sites myself, but my experience has not been so negative.