I'm inclined to believe this is some kind of attempt to create a loophole so some people can 'try it, then deny it'.
No, masturbation does'nt mean you find yourself sexually attractive and using inanimate objects to pleasure yourself does not mean an attraction to whatever inanimate object it is, but, using objects falls under self gratification, and just like simple hand-shandies AND fucking (same sex or opposite) it is all for personal gratification, your pleasure.
If you take pleasure from having a member of the same sex engage in sexual acts with you then on some level you could not legitametly claim to be straight without being partially dishonest. (i.e, you might say straight but actually you are more bi with simply a greater sway towards straight, 80%-20% eg)