A vast majority of "cold calls" made by recruiters are just bots / scrapers. They scan your profile or resume for keywords and then email you with a generic canned message. That is why they cannot / do not differentiate between "a little experience" and "a lot," it's almost always just a positive hit on the keyword match.
So the appropriate response is to just delete the message if you are not interested.
If you are interested, then reach out to them and they will discuss your experience and capabilities at that point and tell you if they think you are a good fit or not. Most jobs have flexibility (within reason) with regard to the requirements. You won't know unless you ask.
Even if the recruiter did read your profile and write you a message, he either made a mistake or misread. I think the rules still apply for a cold call... if you're interested you reply, if not ignore.
There is clearly no match for the current offer but I would not mind to hear about other relevant opportunities.
Then this sounds like the perfect thing to mention in your reply.