Isn’t it though? Isn’t all the coding their intellectual property? It’s all their assets. Even if you create your own tricks or whatever, it’s based on their initial base coding.
If you’re not allowed to charge for edits (even though some people do) then nobody should be allowed to charge for any kind of coding, directing help, templates. Even those “buy me a ko-fi and I’ll give you my templates” shouldn’t be allowed.