Prove it - we do't understand consciousness enough to make such claims. Or at least have the wisdom to apply the precautionary principle when you don't know.
N.B. I don't believe we fully understand consciousness. Just that factory farm animal consciousness is categorically not at a human level.
It's a science, not a 'math thing'. Yours in an old fashioned conservative retreat into avoiding reason or ethical considerations.
BTW I don't consider myself an activist.
This notwithstanding, the ethical concerns seem premature. Shouldn't we wait for information on an actual concrete proposal? Perhaps it can be done with very little of the brain and when coupled with FMRI we can be sure enough that it isn't experiencing conscious states. But all this seems premature and subject to the actual details.