If I were to make such a statement, you can "bet your bottom dollar" that I would have a reason for thinking that way.Well you cannot just state viruses do not exist without at least some reason for thinking that way.
If I make some statement - and, you do not understand "why I think that way":
~ Am I automatically wrong?
~ Is there even the most remote chance I could possibly be right?
~ Might you be genuinely interested in understanding why I think that way?