I see nothing inherently "wrong" with FEMA's list. It is a list that is far better than nothing. If everyone had this kind of kit available when needed it would make a big difference.

FEMA is in the tough position of trying to navigate a minefield here. They can't really tell people they need to consider that they might well be on their own for weeks without outside help as that would trigger all kinds of unpleasant questions about how that could possibly happen, despite it happening on a pretty regular basis.

They cannot tell people to have guns or effective knives because that is moderately political in nature, and not always legal, despite being often useful in disasters. plus, if you take your guns/knives to a shelter set up by FEMA, they will make sure they are confiscated. They are not going to tell you you should have something they won't allow you to keep.

I don't think three days of water is enough, but I don't know how much is. Is 5 days enough? Ten?

Matches or a lighter have started many a fire. Probably the vast majority of fires that have ever been started deliberately. I see nothing wrong with it. Is it the perfect fire starting solution? No. Nothing really is, but it is far better than nothing.

How much food do you need? Most people can live a long time without all that much food. It's a lower priority than other things IMO. Few of us are going to die or be much more than inconvenienced if we don't eat for a day or two.

As for shelter, a tube tent is cheap. It provides some minimal level of protection from the elements. It takes up little or no room.

Part of the challenge of this kind of list is making the kit small enough and cheap enough that the average person who never needed one is actually willing to create one.