Ugh. Hate this sentiment that some people are language designers, and others simply aren't. So pretentious. If someone is designing a language they're a language designer, they don't need your approval.
And yes, designing the distribution, branding, community, and leadership around a fork of an existing language counts as designing a language. Just because the speaker's "team" seems to be lacking in those aspects doesn't mean they aren't an important part of language design.
Regarding the "full find and replace", they haven't gone through to change path names because that'd cause far more trouble in synchronization with upstream than it's worth. Accordingly, they haven't changed source text that references those path names. Knowing which changes are appropriate versus the ones that aren't takes far more "language design" know-how than simply doing the "full find and replace" the speaker suggested.