I have twin boys, and my MIL was a big fan of buying identical outfits (a few other people did too, but MIL was the biggest cuprit) she probably did it simply because I didn't want them to be dressed the same, yes, she is one of those MILS
I never dressed them the same, I didn't want to, just because they are twins does not mean they are the same person though quite honestly with my two they are like the same person split in two
But when they started choosing their own clothes for the day at about 2yo they constantly picked out the identical outfits rather than individual ones. So I let them.
Not my choice, but it wasn't worth arguing about.
While identical, my boys do have slight differences in their features, sometimes you really do have to look though.
They dress differently again now at 8, have done since about 5ish, reverted back to dressing the same (or very similar, ie same top in different colours) when their sister was born, and will revert back to it if one is poorly, or feeling insecure (one had a horrid teacher one year, so dressed the same as his brother every day after school for that entire school year, but differently on weekends)
Also, they have to wear uniform at school, which is surprise surprise identical, so you kind of have to learn which is which by them themselves, rather than the colour of their clothes... Being boys I can't very will stick a different hairslide on them now can I?
So before you hoick up your judgey pants, maybe wonder if it is actually the childs choice, rather than the parents.
I don't get why it is such a big deal, I don't necessarily think it is 'cute' as they are often going for, but I don't think it's something to get worked up over. I was always being told I was a 'terrible' Mum for dressing my twins the same, but at the end of it all, my children were happy, they were healthy, they were well taken care of and very well behaved... I didn't realise choice of clothing could make you a terrible parent, but hey ho