The article is wrong about the rainbow and pride. It is clear from he article that the rainbow flag was stolen from a group of female Freemasons even though the article claims it was stolen. Regarding gay, it meant happy but was also a slur against fags in the way that queer was and they just "reclaimed" the word. So they didn't actually steal those words. They just made people think it wasn't a slur. The article doesn't make any attempt why the word pride isn't stolen. No one is not telling them to not use the word pride but it requires an adjective or noun before it to denote what they are proud of.
http://canyonwalkerconnections.com/gays-didnt-steal-the-rainbow-or-the-word/ Now they call a whole month "pride" without even saying the word month. I guess they have their own calendar with their own month names, one of them being a month long holiday, just like Muslims have the month of Ramadan as a month long holiday. Their holiday happens to fall during June of the Civil Calendar. I guess they want to be like the French Revolution which made up new month names. But people that don't belong to the gay culture should not be expected to use the gay names of a month unless they make clear that they are referring to a homosexual event. Using the word pride is not clear by the rules of language (even though it is clear by the made up rules of "political correctness".