The most important part of this is the primaries. If we fill these seats with a bunch of Chuck Schumers/Hakeem Jeffries it won't make a difference. If we fill them with Zohran Mamdanis, on the other hand...
Yupp, don't let them tell you yet another "compromise" candidate, who "at least isn't the red elephant person" is gonna cut it. They have been losing elections, they spark no enthusiasm, they are not the "safe option".
That being said, do organise and network outside of party politics, too. Elections are an important part of everything, they to mould the status quo to some degree, and can heavily shift context of further political work - but getting beyond the structural shit that put Trump into power requires more than that. Joining (preferrably radical) unions, showing up to town halls and the likes, networking with neighbours and friends for mutual aid and emergency support, community defence organisations, civil rights orgs, etc. etc. Both informal and formal organisation is needed wherever you can.
‘They’ say that because turnout for primaries is always abysmal, so candidates who make it to generals are usually centrist.
If progressives actually voted in primaries, they’d have the options they want in generals. But usually, the vast majority who vote in primaries are older, more moderate voters.
Progressive candidates exist, but if you want them, you can’t just vote every 4 years.
Which is probably why the DNC didn’t let us have a primary for the 2024 election. They knew their status quo candidate didn’t have any juice behind her but didn’t want to open the door to that criticism.