Edit: And for the bogeyman's sake, if you'd like the "proof", that's what Google is for. This isn't some fringe view. It's about the same as asking me for proof that smoking is damaging.
The main source for recommending limitations on overall screen time for young children seems to be a set of recommendations published by the American Academy of Pediatrics [1], but they don't actually cite any research (or their citations are too well-hidden for me). The AAP recently published a release stating that new recommendations are coming soon and suggesting that the old guidelines are unnecessarily rigid and unrealistic, even to the point of explicitly stating that "The public needs to know that the Academy’s advice is science-driven, not based merely on the precautionary principle.". The top bullet point is "media is just another environment". This newer document generally advocates a nuanced approach that takes the nature of the content or activity as well as the social context of media consumption (e.g. whether parents are actively watching with the child) into account [2].
[1]: https://www.aap.org/en-us/advocacy-and-policy/aap-health-ini...
I love to sit down and actively watch (i.e. point, name, discuss) a show with my 3 y/o son. When not excessive, I feel this is good for both of us.
While I also agree that it doesn't feel wrong to experience something on a screen as a family, we should always be wary of "it feels good/right" as a reason for believing that something isn't bad for you in the long run. That's a slippery slope that has led to plenty of negative trends recently. It's far too easy for people to latch onto things that are good in moderation and let those things slip into over-saturation.