The correct response, I would imagine, is that if someone says that "there is no higher power", then you ought to respond, what makes you say that? Any statement of fact must be justified. Even if someone said a higher power doesn't exist, in a debate, they are not immune from attack just because they share the same view as you (obviously we are all biased though). All opinions with no/poor justification ought to be shot down, but especially those that are perceived to be incorrect because they are generally more harmful. For example, a child believing that boiling water should never touch ones skin but he doesn't know why isn't as harmful as a child believing that it's ok for boiling water to touch their skin, but also doesn't know why. Two unjustified beliefs, yet one potentially leading to more serious consequences.
Yes, but this is a debate forum, and with debates in general you state I believe x because [reasoning]. You have provided reasoning, but it is poor and fallacious. You are saying that you believe that a higher power exists because I don't know how x (evolution) could otherwise be explained.
This structure isn't good for anything. Play the substitution game. If someone knocked on your door and said I believe that you killed my dog because I don't know who else could have done it. Hopefully you can see from that why the argument is structurally wrong. It's all good and well to have opinions, but it's even better if you can justify them for everyone's sake. The better your justification the more confident you can be in your beliefs, the more people will respect you, and the more intelligent your thoughts can be. We're not 'insulting' your reasoning because we disagree with you, we're insulting you're reasoning because it is objectively wrong; this is not a difference of opinion, this is the identification of a logical fallacy.