I think you'd have better luck trying to argue the point of why you
can dribble than as to why you
can't. Specifically, look at rule(s) 7.6.1 - 7.6.4.
For that matter, I don't see why it's a problem to let a player dribble on a
spot throw in--so long as they don't stray from the spot. Where's the advantage/disadvantage in this???
The only argument I could see being made is rule 7.6.1 says "...The thrower shall release the ball on a pass
directly into the court....The throw-in pass shall touch another player...on the court before going out of bounds untouched." I guess you could argue the dribble was in fact a "pass," and it never made it inbounds before it touched another player
Like the old proverb says: "If the rules don't say you can't do it, then go ahead and do it."
Well, at least that's my proverb, anyway.....