I think the simplest way to describe it is that it's a religious conflict.
A not insignificant segment of people who develop and/or use Linux are fervent followers of POSIX philosophy, the Unix heritage, Free Open Source Software development, and the Anti-Microsoft Church (note: Poettering is a Microsoft employee).
These people have a religious duty to hate systemd, it's essentially heresy. It's not a disagreement based on technical or even practical merits, so the conflict can't be addressed with technical debates and will continue for the foreseeable future.