I have cooked with cast iron for years and have never cracked one.
I have destroyed a bit of seasoning, but surely not with mild dishsoap.
Normal modern dishsoap does not have any strong lye in it (and hasn’t for decades) and will not destroy a proper seasoning.
And obviously I don’t wash my pan while it’s ripping hot.
Usually I do my dishes after eating, sometimes the pan is completely cooled down, sometimes it is a bit lukewarm, I never had problems with either. If I can handle the pan with bare hands it is cool enough to wash with warm water.
Don’t spread outdated information.
The only thing this does is intimidate people from using cast iron at all and that’s just a shame.