At what point does criticism of a young person become petty, wrong, or gross? Completely rhetorical. Not knowing the specific details of Harris' life, my immediate reaction was that he lacks maturity. Maybe he does have family issues or other that make committing difficult. But in general, I don't agree with certain white knights online who and do not think 17 or 18 year olds should not have any semblance of maturity or professionalism.
Millions of high school students make commitments to universities across the nation every year. It's a huge commitment and life-changing for families. The moving, financial implications, etc. It's not something to be taken lightly and these high school students have some degree of responsibility in making this significant. If you're going to commit, make sure you make an informed and mature decision. Again, if unforeseen circumstances negatively affects a recruit's life and forces a decommit, that's understandable.
Now trashing potential recruits for picking different schools is pretty low and gross. I don't even feel comfortable reading tweets of people encouraging recruits in a positive manner to pick their school.