I strongly doubt that the person you were responding to was asserting that "no person, at any time, in any circumstance, can ever gamble online without it being an irresponsible act".

But chances are that the original commenter was really using language in a more colloquial way, the way someone might say "the only responsible choice is not to use drugs". Someone saying that isn't making a statement that "no person ever, under any circumstance, can ever benefit from consuming any drug".

It's not an absolutist statement, but you are choosing to interpret it that way so that you can construct a response based on semantic pedantry.

Goalposts built around strawmen are almost designed to be shifted.