Point being the assumption that an 18 year old is mature enough for gun ownership but not to drink or have a good opinion is laughable.
It really is. Your argument is a nice dance but the hypocrisy is amazing.
If you are going to trust them to vote at 18 then they should have a political opinion taken seriously and not be dismissed solely on age.
And just for the record amendments can be appealed. They are not permanent to the Constitution. By very virtue of the concept of amendments means they can be added or removed by the will of the people.
And that is where this fight is headed. First the NRA. Then eventually this.
The constitutional distinction between gun ownership and drinking is a clear one. I think what you are saying, inferentially, is that you wouldn't have designed a constitution that ensured that 18 year old citizens would have the same right to bear arms as older citizens (I'm not sure whether you think the age should be older, or that there should not be a right to own guns at all). The design of constitutions is a certainly a debatable topic, and certainly many different approaches to the subject have been implemented around the world. However, I think what could be said for the American constitution is that, under it, the US has become the most prosperous and influential nation in the world in a relatively short period of time. Places a large onus on anyone who wants to argue with success.
Teenagers can vote at 18 because that is one of the rights of citizens. However, the political influence of 18 year old votes is proportionately insignificant (and that would be true even if they actually went out to vote, which they generally don't). 18 year old votes don't dictate public policy. The vast majority of voters have a significant amount of life experience (and many have significantly more education) to inform their political views, and that vast majority exercises the vast majority of political influence.
I'm not dismissive of teenage views because of age, but rather because of the lack of experience, wisdom, and education that youth entails. On the other end of the spectrum, I'm dismissive of past-due milk as well, not because of age, but because of what that age entails.
Amendments can be removed - with great difficulty, by purposeful design. If 18 year olds think they can influence enough citizens to support repeal of the 2nd amendment, first they'll have to prove why they possess some unique insight that makes their view persuasive. Being a shooting victim (or near victim) does not make you an expert in policing or public safety. It would likely engender strong
feelings about the subject, but not necessarily strong
thoughts.