And if you’re still opposed to it, the solution is regulation - not criminalization.
It's why there is an age of consent that no kid can waive.
It's why kids aren't allowed to do lots of things, like vote, drive, drink etc.
There needs to be a compelling reason to make an exception for one politically charged thing that comes with irreversible physical changes.
There also needs to be a compelling reason why that decision cannot be deferred until age of majority.
What does the parent's opinion have to do with it? Their opinion is equally ignored when it comes to statutory rape, no?
This is not a "this is a private matter between the child and the parent" scenario. Some things are, but a clear majority of people do not feel that this should be one of those things.
Reading their comment charitably, one might want the trans youth to also get their information from actual medical professionals and groups rather than random internet strangers.
Analogously, sharing information about DIY at-home abortions with people on the internet is also dangerous as hell and will hurt people. In the world we currently live in it may be better than the alternative, but in a better world both of those are not pieces of information that anyone should need to find online.