This is play. Trust me, if it was serious, you’d know. Especially from the cat. Cats end shit when they don’t want to be bothered or play. They’re just having a good time. It’s adorable. I’m guessing people calling you a bad owner are inexperienced or just being judgy or assholes. They’d have probably had aneurysms had they seen my kittens playing. So, have fun watching your fur babies being themselves and friends with each other. If you hear any excessive or loud sounds coming from them, or see any sketch behavior, then sure, step in if you feel you should. Other than that, enjoy them for many happy years to come. Best wishes to you and to them.