That rumor is patently false for several reasons.
First and foremost, with our current level of technology time travel is practically, if not theoretically, impossible. There is no way that Morris would have been able to make the trip back to 1937 to destroy the Hindenburg.
This fact also raises the question of motive. Even if time travel were possible, why would Morris expend such an enormous effort to return to the 1930s to commit an act of terrorism? I fail to see how a random act of wanton destruction decades in the past could bolster her support for the socially marginalized in today’s society.
Secondly, merely farting on a dirigible would not be enough to cause the hydrogen inside to combust. True, there could be some danger if she used a cigarette lighter in order to produce a “blue angel”. However the logistics of climbing the mooring mast and getting close enough to the Hindenburg’s outside shell, and then having her “blue angel” somehow penetrate the airship’s thick and specially-treated skin, seem highly improbable.
Furthermore, as Morris is by her own admission somewhat less that spry, and as she seems to attract undo attention to herself, I doubt very much that she would have been able to get past the guards at the base of the mooring mast in the first place.
Thirdly, although the exact cause of the fire is still not known to this day, the conclusion drawn by both the German and American investigations was that sabotage was not a factor. Had such an ostentatious, gassy, time-travelling saboteur arrived from the future (no doubt with photographer and camera in tow) I’m sure that her presence would have been noted.
Not being an expert on these subjects, I have no idea about your other two accusations regarding Silkwood and the Lindbergh baby, but I also suspect they are fallacious (mostly vis-à-vis the impossibility of time travel).
You should think twice before posting such nonsense on the Internet.