The funny thing is, in my own games orcs and similar humanoids can be anything they want, even if many are evil by human standards. I just object to giving people a hard time about it if they play differently at their own tables.
In my games, I've tried something slightly different: removed all mention of "good" and "evil" from characters, monsters, gods, and spells. So, Protection from Evil is just "protection" and protects against things attempting to harm you. Detect Evil doesn't work.
If the PC's continually charge into the neighboring Orc kingdom and attack their villages, then, in the eyes of the Orcs, the PC's are "evil", and the Orcs, if its in their best interest, will respond. In the eyes of the PCs, why, of course, the PCs are "good" for going after the "evil" orcs. And vice versa. In an Orc's eyes, there is nothing remotely "evil" in their society and what they do and how they go about doing it, they're good, and regularly attacked for no good reason by those humans over the hills.
They're all free to act and react as they wish based on their society, or their individual personalities, without being "good" and "evil", which, really in DnD and other games, are there purely as game mechanics: see spells, alignment, gods, magic items, etc.
Ultimately each table will make their own decision how they engage with morality in their fictional worlds, as I'm sure there aren't very many people who aren't aware of these particular types of discussion nowadays.
Edit: Oh, and it goes without saying, that Session 0 deals with these types of issues in any game to be played (or should), so, yeah...