The starter may be a non-issue. E.g. starting a drone that way (with a drill) would be fine. Maybe even leave off the exhaust. Depends on the application, which they admit.
This is true but the engines they're comparing to have all of these things. You could take the starter etc. off of those engines and it would weigh less, too- it's a misleading comparison.
You take off all those things, those engines still weigh 20 pounds. You put the mini-versions of all those things on theirs like they show in the video, and I doubt it breaks 10. It's probably overstated bragging, but they've got much to brag about.
Then don't cheat by comparing the weight of the motor with starter to the one without a starter. They are comparing two very different things to produce a spectacular head line.