From what I understand, the devs are not injecting their political views into the Lemmy code. That does not mean they have not had a pro-tankie influence on the Lemmy community. As the original developers, they also set up the first major instance, lemmy.ml and they moderate that instance to have a tankie lean. Since it was the first instance, many people created their first account for it and it was the de facto standard place to start communities. As far as I know, it is still one of the most active instances.