[tomp]

you need to educate yourself better about "basic facts about biology"

they're called essential because humans cannot produce them internally, so we have to consume them (though you could in principle make the same assessment for other animal species, but that's less relevant, unless you're, I don't know, raising cows?)

plants don't eat, but produce organic molecules from raw ingredients (or almost raw, in case of nitrogen), and can produce all amino acids - but in different quantities, so maybe the (parts of) plants you eat don't have all the necessary amino acids.

[DetectDefect]

Now they do produce all the essential amino acids, but in insufficient amounts? Weird how the narrative keeps changing in this thread. A serious lack of scientific knowledge is apparent from people who insist on eating animals. And as always, it is devoid of any backing evidence or credibility other than "trust me, bro, I lift".

[snophey]

From your tone and the fact that you're quoting things nobody in this thread has said, I'm not sure that you are actually interested in hearing any scientific argument. You certainly aren't trying to make one. But I'll try:

The quality of a protein is measured using PDCAAS (Protein digestibility corrected amino acid score). It's a score between 0 and 1 that measures the quality of a protein as a function of digestibility and how well it meets the human amino acid requirements.

It is indeed correct that both lentils and chickpeas (which the original comment you replied to was talking about) have a much lower PDCAAS value of around 0.70. Data on beef varies, but it is generally considered to be a complete protein with a PDCAAS score above 0.90.

Instead of accusing "people who insist on eating animals" of lacking scientific knowledge, it would have been much more helpful to point out that the highest quality proteins on the PDCAAS scale are almost universally vegetarian or vegan: eggs, milk, soy, and mycoprotein all have higher scores than beef, chicken, or pork.