[amelius]

Because it is generally a good idea to have a diverse diet.

And also because there have been concerns about phytoestrogens in soy. Whether true or not, the former point still stands.

[paxys]

Covering some portion of meat proteins to plant-based ones is going to result in a more diverse diet for most of the population.

[YeGoblynQueenne]

This assumes that most of the population does not already get most of their protein from plant food. This really doesn't seem the case, considering what are thought of as "staple" foods in most of the world: wheat, maize, rice, cassava, potato, sweet potato, etc. A diet where most of the protein comes from meat is more typical of developed nations, and then again, only some of them (hint: the US).

[ahelwer]

Those concerns are pseudoscience pushed by right-wing figures, please stop spreading them: https://youtu.be/C8dfiDeJeDU

[wskinner]

This seems somewhat unfair. According to a summary of the relevant research [1], the actual effects of phytoestrogens in humans are not fully understood, and may be different for Asians and non-Asians. Calling it right-wing pseudoscience is excessive.

[1]: https://www.hsph.harvard.edu/nutritionsource/soy/