It's being downvoted because the commenter made no effort to show what kind of research they had done in order to relieve their worry. If they genuinely were "really really concerned" about the potential side effects then they would have done some research on what those effects could be, what scientists had done to account for them etc. If they have done no research, that is lazy, hence worthy of a downvote. If they have done research but not specified so then it is deceptive and worthy of a downvote.

This is getting worse than Stack Overflow.

So you can't ask a question for more clarification unless you spend hours researching the subject?. I can get that if it's a coding question and someone was looking for a solution. But this is a scientific subject and there is a pool of knowledgeable HN users who can help with this kind of questions.

I am not saying that simple questions deserve a downvote. However I do think that questions that are not asked in good faith should be. In this case, the person appeared to either be exaggerating their level of concern, or deliberately trying to cast doubt on the scientific process in an effort to sow distrust.

If they had simply removed the "really really" from the question I don't believe it would have been perceived in the way I gave above. You are trying to claim that this was a perfectly innocent question which it may well have been but you should also be aware how it might be interpreted differently. You have not mentioned how you believe bad faith questions should be treated on HN but I would guess you would agree that some of them would be deserving of downvotes.

It shouldn’t be like that. Simple questions are completely acceptable on HN.

I totally agree. If you interpreted the question as "simple" that's fine. All I did was try to explain how it might be interpreted as a question that was asked in bad faith (i.e. with some relevant information deliberately omitted).