My point is that it's incorrect to say the people who play tee ball unanimously call it T-ball. Whether or not T-Ball USA is a leader in its field, it's obviously pretty well invested in that field. T. No, it isn't. The players wear T-shirts. By that logic I play polo every time I step on a tennis court.
T is an abbreviation for tee.
That sounds like homonym confusion to me. I can't blame them. Absent an emergency meeting of the style committee, that's what they were bound to do. No, my quarrel is with the dictionary people. Not yet, anyway.