Yes. This is absolutely correct. The generally accepted view is that prehistory ended and history started on the North American continent roughly mid 1490's.
This only sounds prepostrous if you don't understand what the terms mean.
This is also roughly the timeframe when the last stone-age society near Europe finally got subjugated by Europeans and stone age finally ended in the old world, when the Spanish crushed the Guanches in the Canaries.
This is fine if everyone in the conversation has that same academic definition of pre-history - the problem is that bad actors will often latch onto that statement, ignore the definitions, and use that as a basis to argue that so-and-so people were sub-human.
It'd be really nice if all parts of the internet engaged in good faith debates on topics they were knowledgeable but finding that phrasing preposterous isn't unreasonable if you've spent a decent chunk of time exposed to reddit and twitter.
I agree that you're correct and reasonable, but I also agree that the person you're replying to was correct and reasonable when expressing caution over how things are worded.
Are we still not counting wampum belts or khipu as a written language? I know that those are both very different from how we comprehend written languages but there is significant evidence to support that they were used in the process of imparting information (whether that be treaties, legends, or statistics)
A language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary.[0]
I don't think NA wampum or totem poles would be considered written language by that definition.
Khipu aren't found in NA, AFAIK.