All you’ve explained is your opinions. Your “arguments” are just opinions. But you are stating them as if they are facts.

Polling showed that border control is important to more than just republicans. So dems did their job and said they would address it.

You came up with some conspiracy theory that no one cared about border control until dems said they would address it.

"You’re pretending that the verbiage didn’t change to ‘don’t vote/vote 3rd party because of this’" Yeah, it absolutely didn't change to that.

What happened on lemmy.ml was Russian bots posting bullshit. And I won't deny those posts were posted and comments commented

You deny the verbiage changed to “don’t vote/vote 3rd party” then you admit that it happened, claiming it was only bots.

The reason bot farms exist is to change public opinion. They claim to be someone they are not and repeat talking points until other who are not bots start repeating what they say. In this case other leftists.

the critique from the left was constructive and included how to change the messaging to improve the odds

You claim that it is just critique. In reality it is a tactic called FUD used to discourage voters.

How could leftists, who are such a small part of the voting populous possibly know how to run an effective campaign better than a team of strategists that have been doing it as a career?