why?

Why celebrate a pointless day, and reinforce it by making it official. Seems a bit, pointless...

Can someone explain what's "woke"? As I don't use social media.

As KasperHviid said, it's the idea that all people should be treated with respect, regardless of age, gender, religion, sexual orientation and so on. As to the question "why would anyone be against that?", the answer is equally simple: Some folks feel the idea mildly infringes on their vast privileges.

The question "Why now" has more complex answers.

One factor might be that since the TRoP teaser hit, a bunch of predominantly Russian men seem to experience their heads reflexively exploding and their genitals falling off.

dont listen to what these lie
that is opposite of what woke is
imho search for it online and come to your own conclusion

Woke people yell, cause chaos, violence and riots. They feel that they are entitled to other people's respect no matter what their actions are. They yell about other people being privilleged and them being disadvantaged when that is obviously not true. They like to blame others for their failures and demand respect while at the same time acting violently. They are usually of low intelligence, entitled and demand respect while they don't act as decent human beings. They also like to think of themselves as progressive

@DavidOrion93 "Woke" is a derogatory term for annoying, conceited, self-absorbed and somewhat spoiled youth who, while being activists in actually quite agreeable social campaigns, manage to put up a very teeny confrontational attitude and unreasonable, over-the-top, nearly identitary claims that just are not in touch with reality or average mindset of their environment, thus becaming some sort of well-meaning radicals easily triggered and well used to ferocious quarrels.
It's basically the same of youth subcultures or urban tribes of my Nineties, complete with bitter rivalry that stems from subtle and minor "clanic" dos and donts, but somewhat mixed with politics and tentatively justified with a naive and impulsive take on social reformism, in the same way we older ones used to cling to arts, fashion and music back then to set us apart from the "others" we did not like.

I generally dislike arbitrary celebratory days (or months), but wokeness is cultural cancer, so I'll bite before GOG shut down the thread.

Happy anti-woke day indeed.

If you have to ask, you don't want to know.

I know that sentence doesn't make sense and is contradictory with itself (because you ask specifically because you want to know), but hey, that's life for you.

wokeness is political and cultural subterfuge. It's taking real issues and twisting them into some dark, twisted, hyper partisan authoritarian tool of control, instead of actually doing anything that would actually solve those issues.
It's uniquely American and quite insane

We're all under a thick blanket of lies over here.

Woke means Identity politics.
Which means focusing on a persons race, sex, gender, age, disability, etc, above all other things.
Which turns into their own kind of weird hierarchical structure of victim-hood points. The more points, or "unique" traits you claim to have, the more you should be listened to and respected/gain privilege.

Like with many similar artificial constructs from the left, it means the opposite to what they claim.
Equality for us means Equity for them. Anti-racism for us means less white for them. Anti-fascist means acting like a fascist. Diversity means of the above mentioned superficial traits, not thought. Inclusive means excluding straight, white, men, etc.

Typical examples in corporate culture is playing on this to be seen as hip. Sporting rainbow flags, black squares, hiring quotas.
Within the arts you can see diversity-washing. Which means changing a typical or known characters traits from what it used to be to something within the oppression hierarchy. The reverse is racist though. Cultural appropriation.

You should be anti-woke every day.
It's a form of mental illness and a cult.

At its core, "wokeness" is a worldview based on class struggle. For woke people, every society is divided between oppressors and oppressed. And those who are designated as oppressors are declared to be responsible for everything bad while deemed oppressed are given a free pass for even the most despicable things they do - after all, they are just victims, and that excuses everything.

From this point of view comes everything - declaring white straight men as the source of all evil, a constant demand for reparations or privileges for "minorities", various policies that are meant to treat people based on their race, gender, or other identities. And that's why woke ideologues constantly blame white straight men for all that is wrong in the world, push for "awakening of race awareness" so everyone would always remember their race and treat people according to their race, invent new genders and groom children to be ashamed of their own bodies, call traditional family an institute of oppression, and.... yeah, pretty bland. Never doubted that.