Why KYC is bad?

Hello fellow Bitcoiners,

I am quite new in Bitcoin. I just dumped all my shitcoins after reading about Bitcoin, and I moved to a hardware wallet. Now I am trying to understand the privacy exercises.

So far I bought all my BTC from exchanges like Coinbase, and Gemini. But what I see here in this sub, folks are buying from non-KYC exchanges and use coinjoin stuff to increase the privacy.

I also prefer using each BTC address once and so on, but I don't really understand why KYC is bad.
Could you please share your thoughts about KYC? You avoid them only for taxes, or do you have other concerns as well?

Thanks for your comments in advance.

PS: I am smart enough to not reply any private messages.