don’t know if I just blow this off or make an attempt to inform them regarding the questionable history of their denomination.
–Blow them off. Your efforts to inform them will IMHO likely backfire on you. You will not convince them.
These folks - like JWs; Mormons; whoever - have “higher authorities” they can call in “as needed.” You will NOT want to get into debates with them, in part since many of these folks are professionally trained apologists; slick presenters, etc, - and worst, they will simply lie.
Worse, the underlings will, with a smile, present these (false) authorities as “someone who can answer your questions better than we can,” etc., as if these “authorities” are friendly. They are not. They are there to convert you and, if you’re really sharp, to prevent their own underlings (your friends?) from being swayed BY YOU. These folks protect their own like they guard the PIN numbers to their own bank accounts. You will end up doubting your own faith.
In fact, if you think about it, the material I posted shows that even many SDAs themselves believe their own tactics are deceitful - yet they engage in them, over and over.
Look, sadly there are just too many anti-Catholic haters out there, particularly on the internet, and debating them is like nailing jello to a wall: You just can’t; you will be frustrated; they will eventually either i) slither away or ii) through their own tactics, slick presentations, etc., make you question your faith (which is in fact just what they want).
By far the best thing you can do is find groups of like-minded CATHOLICS who share your faith and whom you can grow in community with. But the SDAs? I’m sorry, you’re wasting your time with them. You’re ahead now; I’d quit with them while that’s still the case.
PS/EDIT: The higher you go in dealing with the SDAs, the more strident anti-Catholicism you will encounter. Your friends may be sincere. Those higher than them will not be. Real anti-Catholicism is very, very scary.