If it is always outlandish then yes, necessarily.
You said "putting words into people's mouths is always outlandish."
Of course, I disagree.
There's a old joke - you've probably heard it in a variation - a woman buys two dresses for her daughter-in-law. On the next visit to her son, the daughter-in-law wants to show her appreciation for the gift and decides to wear one of the dresses. When she opens the door to greet the mother-in-law, the mother-in-law says "The other dress you don't like?"
The implication you make is not necessarily an implication that is inherent in the facts, and it not generally fair to attribute your implication as the speakers intention.
Is the statement that cyclists should wear helmets "victim blaming"? If you'd just been hit by a car and taken a good whack to the noggin you might think that, but you'd also have to think that the comment was directed at you.
A very simple implication from Trump's words is that he is a person that believes people have a responsibility to look after themselves and their communities. In that subsequent facts have shown that some people did report their concerns means that his words are merely uninformed. It also shows that there IS work the government can do - properly fund and run the systems it has already legislated into place.
Another thing that we can imply from what we have come to know is that most people don't report things, think that it's someone else's problem (or responsibility) and that nobody really cares until something bad happens and then it's someone else's fault. This kid was on a course to do something at some time, kill someone or kill himself. Most of his community didn't give a damn, they either teased him or punished him or both. Some people tried to help but they didn't really know what to do or who to turn to - because there really isn't much for kids like him.
When something like this happens there's a lot of people asking what went wrong, but Trump and his opponents both seem to be convinced that they know what went wrong and who is to blame. When something terrible happens, the first thing to ask is : is there anything I could have done to prevent this? and then expand the circle - because you are the one with the most interest in you. And this isn't just a problem "over there" in America or in Florida or in Parkland.
Will anything change? I doubt that it will because, quite frankly, this is not America's biggest problem. Shootings like this are still rare considering the population size, there are so many guns in the culture and the world that getting rid of them is a task too big to accomplish. There are all sorts of economic interests that will be in the way, too many cultural interests and both parties love having something to fight about so much that they would hate to actually DO anything about it and have it settled one way or another. America, more than many other western countries, is a place of cities and vast empty places. If you live in a city you are more likely to be anti-gun because a stray bullet is more likely to be a danger to you and your loved ones, whereas there are plenty of places in the US where you could go and not have a chance of hitting anything with artillery and where a gun is a tool to kill what you want to eat and what wants to eat you.
Getting back to the issue of the tweet, the Don's tweet was simply uninformed. It wasn't even wrong per se, just not very useful. The backlash IS useful to certain political operators who love to puff up anything they can into outrage - a force more dangerous than just one autistic kid with gun. Trump didn't say "The kids that got shot deserved it" and people who pretend that he did are dangerous.
