Yes like any other celebrity Ian and Anthony have had their share of times being problematic.
Why Anthony is problematic: he gets too over the top about veganism (although he has stopped that awhile ago) and how he reacted to Ianthony shippers (even though he was stating his opinion he was a bit rude). Like I understood Anthony is a passionate vegan but insulting meat eaters was too far for me. That's why I'm glad he has stopped that. And well for what he said to shippers, idk how to feel. I think he could've told his opinion on Ianthony without being rude to the every shipper. Anthony hadn't made any comments on his actions.
Why Ian is problematic: he made self-harm jokes in the episode of Gametime where they play Little Big Planet 2 (around the 2:30 mark). Also more recently he tweeted about a video game character that caused some fans to think he was slut shaming the character because he added "slutty clothes/attitude". I somewhat agree with this because although it was supposed to be for comical purposes the slutty clothes part wasn't really necessary. Personally i believe these are just Ian not thinking before he speaks because he doesn't seem like the kind of person to have that mind-set. Ian hasn't made any comments on his actions.
So see, both of them can be problematic sometimes. it's okay to stan someone who can be problematic, you just have to be aware that they are problematic and help them realize it.
What makes me upset is that anytime Anthony says something problematic a majority the fandom attacks him left and right. But Ian? I see like 1-2 people call him out for it because the rest of the fandom is over in the corner like "Ian didn't mean it. It wasn't his intention don't yell at my precious cupcake!" Like seriously anytime Anthony says something he gets blasted with "Anthony is trash he hates Ianthony omfg he is sooo problematic!" but yet with Ian people just defend him with "let people have their own opinions gosh it's his twitter!" Again this is DOUBLE STANDARDS!
Then we have those who always bring up Anthony's past to make him seem like the bad guy and make Ian seem like an innocent cupcake. Like sure Anthony said some things in 2014 and 2015 that were wrong but so has Ian so...
Knowing Ian and Anthony they probably don't mean to cause any harm when they say things that are problematic because we know they are good people. They have apologized for a few of their actions but not all of them as far as I know. But calling only one out and not the other is double standards and it needs to stop. And there is nothing wrong with calling out a problematic celeb. It can help them become more aware of what they did wrong.