As a vegetarian you still pay for animals to be murdered for your personal enjoyment. Every laying hen whose eggs you eat had a brother who best case was shredded alive soon after hatching, or kept around for a few weeks to be murdered for his flesh. Laying hens are murdered once they age out of peak egg productivity to be sold as cheap meat. Cows and their male counterparts suffer similar fates.

My point is that yes, even most well-intentioned communist humans indeed are a plague, and the planet would be better of without us.