Re: Early information
I actually agree with much of what you say - especially about the gangster in the White House, but there are a few things to take issue with:
1) War of independence: This was nearly 250 years ago, with different weapons, and I can assure you that we (the UK) have absolutely no wish to invade you again, and if anyone tried, then I'm sure that your military would manage perfectly well without assistance from the general population! So really, this is a crazy excuse for "exceptionalism" - you're now no different from any other country, and you need to "get over" what happened centuries ago.
2) NRA: I laugh when I see the NRA described as a "membership" organisation - the membership fees are tiny and barely cover the cost of the admin, and the vast majority of the money is sourced from the gun and ammunition manufacturers, and we all know that he who pays the piper calls the tune!
3) Lobbying: Here we can 100% agree, the lobbying system in the US is totally screwed, and when combined with a dumb, impressionable electorate (38% of whom are so stupid that they believe that the earth is < 10,000 old!), this does effectively allow votes simply to be bought through advertising. Of course, the fact that the Supreme Court effectively legalised political corruption recently via 2 rulings (Citizens United & McDonnell) makes that even easier!
4) I made no mention in my most of "assault weapons" or even of school shootings - the problem is ALL privately held guns, and as you rightly say, the school shootings are the tip of a huge iceberg of avoidable deaths.
5) Yes, of course the Dad should be charged - I'm not an expert on Texas law, but some variety of negligent homicide would seem most appropriate - if nothing else it might persuade a few more parents to take better control of their guns (who knows, it might even cut the crazy number of shootings of and by toddlers!).