This is the sort of thing where argument is probably fruitless, but they didn't try to impeach him for being Donald Trump, which is what I mean by an
ad hominem attack. Rather, they (for some values of ’they’; this position was signally
not taken by, to reach for the Democrat in what seems to be an analogous position to McConnell, Pelosi)
talked about impeaching him, but in fact did
not impeach him before he held office, for something he'd done—or, rather not done, namely, for his failure to resolve certain conflicts of interest that, according to a reasonable legal theory, made him ineligible to hold office.
Notice that the Wikipedia article you cite itself cites two sources for the claim of talk of impeachment before election, and, as far as I can tell, neither of these quotes any Democrat by name as calling for impeachment before he held office. This is, again, a far cry from McConnell, who very much went on record from his leadership position as opposing anything Obama might do; and, for that matter, from the Republicans who, on the record, called for Biden's impeachment before he held office.