Why is queen placement on the first turn disallowed?
From Wikipedia on Openings,

Bee - Spider - Spider (in a V formation with the bee at the point): This is an aggressive quick-strike opening that allows the player the fastest possible opportunity to move (on the third turn if necessary); the Spiders can thus quickly block the opponent's opening pieces. In addition, if the opponent answers with the same or a similar opening, it provides the best opportunity to force a draw if necessary as the Bees are adjacent. For this last reason, tournament rules forbid the placing of the Bee on the first move, as this opening leads to a preponderance of draws. Bee-Spider-Ant is a common variation very similar in its mechanics.

Emphasis mine.
Bee - Spider - Spider
Bee - Spider - Ant