5e does use “racial traits” to define most of the characteristics of a species other than age, height and weight though, but… since this is about height and weight, let’s work through what the rules actually say:

In current 5e, the current orc stats have this text under Height and Weight:

"Player characters, regardless of race, typically fall into the same ranges of height and weight that humans have in our world. "

There isn’t really anything, anywhere, in the orc kit that suggests they can’t be skinny or lithe. In fact, the key art for the Orc race depicts quite a skinny orc.

Now, despite this, someone might want to use the rules text to say “orcs are massive” regardless. If you do want to make this argument, the only thing there that supports the statement is a racial trait. Specifically: the Powerful Build feature, which implies that orcs are bulky.

If you argue “traits don’t define the characteristics of a species” then there’s nothing at all to suggest orcs should be big. If you do accept “traits” as being able to define the characteristics of a species, then you can point to the powerful build trait as evidence, but that’s all there is.

The joke in this post here is thus: If you were to take that feature out, you’re just left describing human builds.

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Now you can have any mental image you like, run your games how you want, use whatever interpretation you want… You can say “I know what orcs are like from other media experiences, and they’re large.” That’s all fine. You can do whatever you want.

Just remember that this post is just a joke. It’s saying “look! they removed the only thing that says orcs are big, so here’s what happens.” That’s all.