Honestly, in my childhood opinion, it was fine, just trying out food and drinks (whether from shopping or restaurants), testing electronics and arcade games, maybe even buying some toys or going to indoor play areas.
Though the novelty of it soon worn out gradually, taking a walk and peek at around these areas for anything interesting is good once in a while, even if you're not buying anything.
Edit: on sec thoughts, should I place this in the urbanism community? And just so you know, I'm not an American, so I wouldn't know what butcherism might occur in the implementation of malls.
I agree with you.
I think there's still a limit, as expressed by the fact that malls still devote significant space towards folks sitting or kids playing, for free. Even new malls I've seen continue to have ample communal space. This space is justified as a perk for the purpose keeping the families etc. at the mall longer and spending more, but the result is that there's a significant underlying infrastructure that allows for individuals to exist pretty comfortably and without feeling pushed to spend money. Its still nowhere near public land.
Compare to something like a casino where almost all communal space has been sectioned off and parking usually costs money. Sitting anywhere in a casino for too long not spending money feels uncomfortable. A "perk" of most casinos (free alcohol) is only accessible if you're spending money. In comparison, malls don't have door fees and tend to have free parking.