I added an ugly workaround, a slide to the tutorial that asks users to go into their flags and allow autoplay without any gestures. Chrome extensions should have better privileges for playing videos, fullscreening etc. IMO but it all needs to be hacked around limiting extensions.
Since voice isn't counted as a "gesture" the user can't say "play" to start a a video.
It's not just autoplay it's any sort of dynamic (js initiated) playing of media.