1. Argumentum non sequitur. That is, your argument does not follow. Your example of handicapped parking in no way ties to the subject at hand: that an unsupervised child willingly climbed over a fence and jumped into a water feature that nobody is supposed to be in. Handicapped parking spaces are one of the conditions of the Americans with Disabilities Act. Swimming in a fenced-in area meant to keep people out is not.
2. What I promote is a radical new idea: that living children, regardless of how upset they or their family might be given their circumstances, are actually preferable to dead children. Fortunately in this case, the child was quickly retrieved by security cast members.
But what happens if the kid decides to do it again?
Let's say they go to the Magic Kingdom, and he slips away to take a swim at Tom Sawyer's Island....and winds up getting himself caught underneath and crushed by the bulk of the Liberty Belle.
So yeah, let the family complain about being asked to leave, let them hire a lawyer and threaten a class-action lawsuit over their child's disability....but in the end, they get to return home as a family.