I read in the media somewhere, some time ago now, that a body the US had investigated and found that chlorinated chicken did result in a small additionan number of cases of illness and death. But that's not the main issue. The main issue is that low standards for the livestock means a worse life for them, and by ignoring their needs the producers can undercut produce from those adhere to decent farming practices. It would mean that the market became an uneven "playing field", and it would create pressure to lower our own standards. It needs to be nipped in the bud.
The last I heard was that the government wasn't prepared to legislate against it yet; but that's some way from betraying the nation, and the farming industry. I think we need to wait until it's generally understood to have been dropped, then you have a good reason for a lockdown breaking rally outside parliament.