I don’t so much look to defend the D party as it stands, but rather the functional operation of the nation. The D’s are a far broader scope than the R’s and frankly I’d have loved to see something like a Sanders/AOC ticket created for president, but that’s not happening soon.
The Republicans have long been the party of NO. For them, a government de-fanged and paralyzed is a perfectly good thing, it would let the rich and businesses pillage and plunder unchecked. Let them oppress whomever they wish and force arbitrary rules on vulnerable populations at local and state levels where party plays a much smaller role. Matters like Roe and Dobbs wouldn’t exist without pressures from national level lelft-ish parties.
The Democrats often as not get the short end of the stick on deals in an effort to get anything whatsoever done. The ACA was a fairly large accomplishment given the opposition in play seeking to protect the existing middlemen and preclude those damn poor people from taking care away from the rich. They often give up things in exchange for protecting some group, the ‘fine you can keep the 47 round clips on your guns, but you have to stop shooting migrants for fun’ sort of deals.
We would all likely be better off if the existing parties where shattered up and the entire system overhauled to provide a more proportional representation, however that’s not in the cards as things stand. The other potential problem there of course is that the R’s would likely end up with maybe 10% libertarian, 20% boring basic conservatives, and the remaining 70% insane swastika wearing nuts. The D’s on the other hand would end up with a dozen tiny slices of varied groups who all want some very specific thing with great fervor. Where that to happen then the larger few groups born out of the R’s would run rampant over society more than they already do.