This is the _Spectator_ (which has, apparently, metastasised to the US). They've never been too big on evidence; it's not that sort of publication. I mean, Boris Johnson was its editor for a while.
I did find a PEW Research article [1] that stated Hispanics made up 13% of democratic voters circa 2019, a growing metric (10% in 2012, 11% in 2004, 5% in 1996). Versus Replublican which was 7% in 2019. But I'm not sure how to interpret these (and what other context may be necessary).
It did illustrate Dems rather greater reliance on non-white voters, so if they lost many to Trump, that would at least support the general direction of the statement.
The Spectator article also states that in 2020 Trump grew his support among Hispanics by "two-thirds", but from what? Presumably 2016, but what was that number? From the PEW article it could perhaps be inferred to be 6%, meaning it would be 10% for 2020, a significant jump toward near parity with the Democrats, a trend which might well engender some of the requisite puzzlement.
[1] https://www.pewresearch.org/fact-tank/2020/10/26/what-the-20...
Please, show us the arithmetic, author. Don't claim arithmetic, and show none. An appeal to an empirical approach needs evidence, not a mere sentence saying it is so.