From what I understand about this rabbi’s outlook, I would imagine he’s just going with his usual topic that various activities that presumably tend to become addicting are made easier to fall trap to by the Satan.
Of course, I am nowhere near as knowledgeable as Rabbi Wallerstein, but I definitely would NOT say that if someone enjoys gambling occasionally, he’s sold his soul to the Satan.
There is unfortunately a presumption that partaking of something in moderation is the same being addicted. Just because I’ll be drinking a small about of wine with my Shabbos kiddush tonight (as I do on a weekly basis O_O) does not mean I’m, C”V, addicted to alcohol.
People tend to lose sight of that.