Because they really care about the team?
I suppose there are two ways of dealing with it.
A: You live it up, you wait until signing day to announce, you do as many visits as possible and basically try to get as much attention and have a good time.
B: You are more businesslike. You choose your team relatively early after careful consideration. You then show your loyalty to said school be not doing any more visits and focus on putting your energy into swaying other recruits into joining you (for the record this could be a defense to visiting another school alongside another recruit).
Obviously I respect the B approach more, I think a player who has made up their mind should start "playing" for their new team as soon as possible. Silent commits bother me because they could be working harder to sway others to go to the school but instead they seem to be focused on getting attention. I might do the same in their position though, but it still bothers me a bit...