I actually disagree that this is the reason for the aversion. Instead I think it comes down to a couple of things:

1. Containers are commodity. For commodities, price wins first, then marketing. Docker is equally free (as in beer) and is far better marketed 2. There are a very low number of people working on systemd-nspawn and a very high number of people working on docker (and the ecosystem). 3. Dockerfiles and images are ubiquitous. They're easy to support from other run times, but if you're already in the ecosystem, what's the incentive to change?

There is also the fact that some people have a knee jerk reaction to hate anything associated with systemd. Although, I think that is less significant than the two reasons you listed.

I think people in generate are happy that systemd happend

yea thats what my general understanding of that was too, people want the most shrink wrappiest and minimal virtualisation boundary