Apple is not a completely closed ecosystem. You can use a Dell keyboard and a Logitech mouse with your Mac Mini, for example. There are legal battles being fought right now to make it even more open.
You have no basis whatsoever for your prediction "If Nintendo was open back in the day, they would not be the Nintendo we know now." That statement is based on nothing but pure imagination.
Open ecosystems provide consumers with more choices. That is an awesome benefit! I like the option to use Dell keyboards and Logitech mice with my Mac Mini. And I would like the option to use other-branded docks and/or converters with my Nintendo Switch 2 as well. It would sure be nice to be able to plug an XReal headset directly into a Nintendo Switch 2 for example. But thanks to this arbitrary limitation, I need a rat's nest of power cables and converters to get that to work.
Asking for this is not "crying," and there is nothing immature or entitled about it. Your penchant for insulting those who disagree with you, rather then presenting sound arguments, isn't going to win any hearts and minds.
There are clear consumer benefits to open ecosystems, so we are absolutely right to want them, and (if we choose) to use legislation to force them.