There are two kinds of ways to end up as a person at what one thinks are the Left side of politics:

• You start by “what are my personal principles” and build up from that up to “what kind of policies follow and advance my principles” and then support political forces that actually ACT thus rather than just talk about it. As your principles include something around “improving my own personal upsides shouln’t come on the backs of hurting or even harming others” you end up left of center (I.e. pro-social rather than merely pro-self)
• You start supporting a political force for social reasons - maybe because of friends or family or because you were compelled to support a “side” because you detest what the other aide does. Having a tribalist relationship with that political force, by default and never actually intellectually analysing with a skeptical eye their words and actions, you trust them, think their motivations are good and look up to their leaders (as a tribalist you see it all as “me” and “mine” rather than merely some people you support as long as they act in a way that matches your principles). They tell you they’re leftwing, so you think you’re leftwing. Note that their actions need not be according to pro-social principles - in this kind of relationship with a political force the link is not a rational analysis of what they do and conclusion that their actions align with your personal principles, it’s an emotional tribalist feeling of belonging, so even ifthey act in antisocial ways a pro-social individual will deny it or rationalize it away (say: “lower taxes for the rich will actually make society wealthier because it trickles down” or “China’s occupation of Tibet freed Tibetans of a backwards society”)

Tankies are invariably type 2.

So are most Liberals who think they’re Progressive.

In fact in my experience living in a couple of countries in Europe people who always vote for the same party or at most rwfuse to vote for one or two elections are almost always type 2.

IMHO unthinking tribalism and the ease of propagandising such people into thinking they’re “good people doing the right thing” de facto making them relentless warriors for those enacting antisocial policies, is the single biggest problem of the leftwing in modern day democratic countries.