Is this normal sibling behaviour?

[HotSince82]

I am an only child so no nieces and nephews of my own, hence asking this weird question on MN.
Throughout my group of friendships/aquaintances there seems to be a tendency for people to be competitive with their siblings in relation to their DC.
For example stating to other people that their daughter is prettier, or better at gymnastics than their niece or that their son is more academically accomplished than their nephew and even showing photos/screenshots/videos on their phones to illustrate their point.
Also expressing schadenfreude, if for example a niece or nephew fails the 11+ or drops out of uni.
It has happened with such regularity in my circle (mainly professional MC ish people) that I'm starting to be thankful that I don't have siblings around to denigrate my DC in this way.
Be honest, is this a common and accepted phenomenon or do I just know a disproportionate amount of unpleasant people?

I don't think this is normal. I have a niece, we're not super close tbh but I would certainly be happy and proud of her achievements.

Between dh and I we have 13 nieces and nephews ranging from 5 to 25.
And no we don’t behave the way you describe and neither do our siblings. We rejoice in accomplishments and commiserate in less successful times.

Not like it with my siblings, it sounds like major overhang from childhood.

Some people are just like that. I don't think it's specific to siblings. Plenty of siblings won't be like that.

I'm glad that nobody has come along to tell me its normal (so far) because I would be quite upset if my children grew up to view their nieces amd nephews like that.