Yes: Reddit threads planted the seeds for veganism because all the counter arguments were so easily disputed

The difference is one of them is there by choice

giving up beef alone should be commended, just for environmental/climate reasons.

Yes, but the post is about veganism, which is the ethical principle that it’s wrong to exploit animals. Cows enslaved for milk are in most cases worse off than those enslaved for their flesh as they are repeatedly impregnated, have their children killed, and are still slaughtered at a fraction of their lifespan just like the flesh cows.