There is not a single fact present in this list. Those that appear to resemble facts are actually self-evident observations that are tautologically true, and the conclusions drawn from them are therefore half-truths at best, and are both unsubstantiated and unquantified.
For example, the first claim that "For every one person who shoots another without cause, there are millions of gun owners who do not....and will not" rests upon the benign observation that "not every person shoots another every day, only some." This is true, but only tautologically so; if the reverse were true, the human race would be extinct.
What this claim alleges is that the number of people who don't shoot others every day is numerically insignificant compared to the number of people who do, and in an attempt to make this difference seem as wide as possible, the quantity "millions" is used to describe the former, which seems much larger than the unspecified quantity attributed to the latter. But while it's true that far more people don't shoot others, what of the ones who do? And what is the rate of offenders to non-offenders across demographics, socio-economic condition and national identity? If the rate of gun homicides is 10 times greater in one area than the rate in another area, is that considered "okay" because "millions" more aren't killed, or do higher rates in one area warrant looking into the possible reasons for such differences?
This is why we need to think about what things mean, and analyze them in terms of definable quantities, not in broad, sweeping generalizations and sophomorically obvious statements that anyone would accept.
Others so-called facts (especially those that involve the use of words like 'can' and 'would', 'if-then' statements, philosophical generalizations regarding "human nature" and sweeping, purely rhetorical claims such as stating that something "will have zero positive effect") are clearly intended to push an agenda, not to present evidence.
And just as a side note, one should always be wary of claims that something "is indisputably true" and cannot possibly be refuted by any other viewpoint, especially when such claims are made numerous times. This is a sure sign that the author lacks support for their beliefs and simply will not open their mind to other alternatives because it is discomfitting to them.