You can argue that “open source” can mean other things that what the OSI defined it to mean, but the truth of the matter is that almost everyone thinks of the OSI or similar definition when they talk about “open source”. Insisting on using the term this way is deliberately misleading. Even your own links don’t support your argument.
Generally, open source refers to a computer program in which the source code is available to the general public for use for any (including commercial) purpose, or modification from its original design.
Open source is a term that originally referred to open source software (OSS). Open source software is code that is designed to be publicly accessible—anyone can see, modify, and distribute the code as they see fit.
In actuality, neither free software nor open source software denote anything about cost—both kinds of software can be legally sold or given away.
But the Red Hat page is a bad source anyway because it is written like a short intro and not a formal definition of the concept. Taking a random sentence from it and arguing that it doesn’t mention distribution makes no sense.
Here is a more comprehensive page from Red Hat, that clearly states that they evaluate whether a license is open source based on OSI and the FSF definitions.