Like you said, the casinos aren't to blame, whether it be for addiction or whatever, like other businesses out there, the casinos owners are also running their business, and who ever chooses to create an account and gamble on a particular casino did so on his or her own freewill, he or she was not forced, and whoever is gambling should be matured enough to know how to control him or herself from getting addicted.
Both gamblers and casinos have the same goal, and that is to win. It's easy to understand that casinos should win because they have the edge, and that's the reason why the gambling industry is booming. We should gamble for fun and not try to destroy a very profitable industry. If we win, we should enjoy it because we are not lucky all the time. That should be our mindset instead of thinking that we can consistently make money in gambling. In reality, the more we push that belief, the riskier gambling becomes for us.
And again, promotion is very legal for every legitimate business out there, the fact casinos run promotion has nothing to do with gamblers getting addicted, addiction is majorly a fruit of lack of self control, not a fruit of promotion ran by the casino.
Indeed, as I mentioned, we have the same goal, and they (casinos) are marketing to increase their profits.