craftmaster,
first of all, welcome to PPRuNe! You will find all sorts of people here, amongst them some people who have worked on and published on the issues of malfunctioning personal electronic devices and other electrical equipment on aircraft, such as myself. (I have even published on this theme a decade ago. But I wouldn't consider myself at all knowledgeable on the chemistry of batteries. I am more interested in the hazard analysis.)
You may also expect what some call "robust discussion".
You have just given us links to three videos. Two of them are by anonymous people. One cuts up a battery. The other lets a laptop battery fire burn. The third is an FAA video, with identifiable people behind it, who are fire safety professionals, and who have names, and whom you can call up on the telephone, which has been presented in public forms since 2007.
Neither of the first two videos are concerned with the theme of what you do if you have a battery fire in consumer electronics on board a passenger airplane. The third is explicitly concerned with that theme, and is filmed by people who are expert on it.
Now, I don't know who made your first two videos. In contrast, I have had some dealings with the FAA fire people, and I do know people at the CAA SRG, and it is evident to me (apparently in contrast to you) that considerable thought has gone into this.
I can also assure you that, given that suspected battery fires have been at the heart of a number of cargo-aircraft accidents, there are a lot of resources going into figuring out how to contain and suppress such fires.
Now, given that, let's look at your position.
First, you made a recommendation that directly contradicted the current best expert advice, based on your self-identifying as "hobbyist" and "not an expert". Now, if you think about it, that is just asking for a "robust" response by people who know more than you do about the matter. So you can hardly complain when you get one.
Second, you said you think the FAA "hadn't really thought about it". This is - let me say, "robustly" - obvious silliness. You very obviously have little dealings, if any, with the FAA fire safety people.
I agree with DERG that we are all still learning about this issue, some of us more than others.
Finally, let me suggest that if you have continual problems with battery fires in motel rooms, you change your battery supplier ASAP.
PBL