I have seen others that were not necessarily liberal argue that way. They completely ignore points where they are obviously wrong and cannot argue so try to pick out any minor thing to pounce on that will allow them to continue arguing so they can say they won when you get tired of it. I always figured it was some sort of debate tactic people are taught. I think it is partly the difference between discussing a topic and debating a topic.
It's just human nature when you've got a nebulous and holistic attachment to an ideology, because it's really an emotional investment in identity politics, rather than something build on A follows B, which must follow C, or 1+1=2 type of reasoning.
Or, you get a single-issue voter/identifier, who agrees with just one thing that has gotten placed under the Left's tent, like their union, women's rights, gay rights etc. but they may not agree with any of the other planks in the platform, or are at best neutral on them.
A lot of us have the relative or acquaintance who's a blue-collar union worker, but is right of Attila the Hun on everything else and votes Democrat, or maybe the religious person who's concept of Christian charity make them to the left of Lenin, but their abhorrence of abortion makes them pull the lever for the GOP every time.
