They hate it irrationally, based on misinformation and mob mentality. There are no legitimate reasons to hate it. There are plenty of reasons to hate the companies and their practices that are developing it, but the technology itself is blameless.
People who use open source models, on local hardware are being caught in the crossfire and being required to disclose what tools you use leads to prejudice by people who hold that irrational hatred and misinformed prejudice. It's harmful with no benefit to anyone.
If there are copied sources then THAT is the problem, and plagiarism easily identifiable, with existing remedies for the crime.
Why do you you feel you have a right to know when it has no impact on you, other than enabling your prejudice? If it's truly bad, it should be self evident and no disclosure is thus needed. The fact that it is necessary to have disclosure to determine if AI was used demonstrates that it is irrelevant. Regardless of what tools were used, the final product should be judged on its own merits and faults. Judging based on the tools used, and not the product itself, is infantile.