I rejected the statement primarily because it is unreasonable, because it is in clear conflict with what other sūtras (everyone agrees are authentic Mahāyāna sūtras) as well as the Mūlasarvastivada Vinaya say about garlic and so on.
Whether sūtra in question is an authentic sūtra or not is a very distant secondary consideration for me.
Alright. Although, earlier you said with regard to negative effects of garlic "No such effects are mentioned in any sūtra what so ever." Well, the Surangama is a sutra and it mentions it, so to say "No such effects are mentioned in any sūtra what so ever" isn't true. You could say it's unreasonable, because it is in clear conflict with what other sūtras say, but even if that is the case, it's still a sutra nonetheless. You can call it crazy and ridiculous, but you can't call it not a sutra. Chan masters are used to being called crazy and ridiculous, that's nothing new.
What I said exactly was:
There is no Indian sūtra of confirmed provenance that makes similar claims about garlic attracting ghosts (rather the opposite is the fact) or rebirth in hell. This therefore can be understood as a Chinese cultural idea in a sūtra without an Indian origin.
While indeed the Lankāvatāra tells us to avoid garlic and so on, there is no mention of spirits and so no.
You see, I was very precise in what I was delineating.
I also said:
I am sorry, but there is no mention of negative mental effects of garlic in any authentic Mahāyāna sutra.
The latter statement is to understood in the light of the former, since I already laid out what I consider to be "authentic", i.e. a Mahāyāna sūtra of confirmed Indian origin. Neither the Brahamjala Sūtra, nor the Śūraṅgama Sūtra, nor the Sūtra in Forty-Eight Chapters can be considered authentic Indian texts. We can also toss in the Vajrasamadhi Sūtra for good measure.
If the teachings in these texts conform to what we know to be taught in authentic sūtras, then those teachings can be accepted — but if there are teachings in those texts which do not conform, then those teachings should be ignored, such as the idea that garlic will send one to hell for eating it.