It is literally association fallacy. And it is bad because it doesn't lead to a good discussion. Instead of actually talking about whether Deno is doing a good thing, the only way I can respond to "Nah, all forms of marketing are bad." is by saying "no they aren't", which won't change either of our minds and isn't a particularly interesting discussion.

You seem to be saying that Deno reclaiming JavaScript is a bad thing? Why?

Well, ECMAScript is not owned by Oracle, and people can use that.