> Yes, it is always fine to question scientific conclusions with legitimate concerns.
See, scientific consensus is usually based on data and certain statistics. Those who question it usually express opinions without addressing the data and methodology. An opinion is not enough, you need to be very specific.
I'm not sure what that means. Whoever makes the claim provides the facts. If you aren't convinced by those facts then you don't accept the claim. You don't need to bring facts of your own to refuse to believe a claim.