I don't think anyone is saying that.
But there is a huge difference in underlying approach between wanting sexual orientation to be non-notable, and seeing it as a major, and public, identity marker, that should be celebrated as different.
Most people go about their daily lives and while family life will get some mention, most of the time sexuality won't except in the context of dating. Is there a need to elevate the concept of sexual orientation to something different than that? Why would their be?
The question of "straight Pride" comes out of that I think. If sexual orientation is such an important thing in itself, that defines us hugely, then there really should be a festival for sexual orientation in general, and in all of t's various permutations, from people who like sex in their socks to lesbians to blue hairs to the fans of cottaging and the most boring vanilla straight people to fetishists.
To a large extent, Pride seems to represent a very small part of even the LGB community. Part of that is because many people, gay or not, aren't wanting to take that second approach to sexual orientation. They want it to be non-notable. But also because it seems to have been attached to a whole list of other political causes.
That's what I find most notable now about all the "Rainbow" people and their allies. Sexuality isn't actually the main commonality, it's politics. It includes lots of people who are, let's face it, straight. And excludes gay and lesbian people whose politics don't fit. Which is a lot because, honestly, this is a group of people where their common beliefs are actually pretty minimal. There isn't an LGB perspective on 99% of topics.