Gore lost because George Bush's brother, Jeb, invalidated a bunch of ballots and stopped a recount as governor of Florida.
Besides that, this argument is absurd as it would be just as valid to say that Gore spoiled the election for Nader and if Gore hadn't run, Nader would have been elected president instead of George W.
Quit trying to externalize the blame for the actions of the party leadership. These faults should have been clear to you in 2016 when they handed the White House to Trump, and again in 2020 when their candidate only narrowly defeated Trump (especially at a time when Trump had already wrecked the economy and COVID was skyrocketing and this was fresh on everyone's mind).
You seem to keep insisting that everyone else needs to adjust to meet you in backing candidates that keep losing when maybe you should be the one adjusting to meet others. Sliding further and further right isn't a winning strategy for Dems and that should be quite obvious by now.
It's definitely a valid concern. In 2020, Trump had federal police descend on Portland in plain clothes and unmarked vans to literally kidnap protestors off the streets.