Trying to be somewhat fair to both sides but gross oversimplification for brevity:

Knots has proposed a soft fork for an emergency one year to block some of the most common forms of what they consider spam to come up with a “permanent solution” that they haven’t yet determined but will develop over the next year. They consider “spam” an existential crisis that could kill Bitcoin.

Opponents(myself included to be clear) have shown this would lock current UTXOs (mononaut and others have posted examples of real transactions) so there is risk coins will be confiscated - which the pseudonymous BIP author has openly acknowledged, and that you can easily put spam on chain other ways with push-data and bare pub keys. I would personally push that forks with known coin confiscation risk are unacceptable. The BIP author also openly admits they only address a few forms of “spam” while leaving the most harmful untouched.

Here is a meme imo to sum up most simply.