Hi! Yes, it is clear that obesity is a huge risk factor for getting seriously ill or dying from COVID-19. This isn't incompatible with germ theory; even germ theory supporting major health organizations have pointed it out. The plausible explanation is that fat tissue has more ACE2 receptors for the virus to latch on to, leading to greater inflammation throughout the body (explained in a scientific article https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7368415/ and on WebMD https://www.webmd.com/lung/news/20200714/why-obesity-may-stack-the-deck-for-covid-19-risk ). It's still a virus ultimately causing the disease, just worsened by an ill-equipped terrain.

If terrain theory were true, and germ theory false, then these patients' obesity (and stress, and exposure to toxins, etc.) would be the whole reason they are so sick, and the virus (if it exists?) would not trigger this severe illness, but rather, be drawn to this sick tissue - so the disease is not a contagion. This doesn't seem right. We know that healthy and unhealthy people alike have had this virus in their system, although the less healthy people get much more sick with it.

I hope this helps clear things up. Thanks for asking!