Yes. I missed the 1992 general election by three weeks, but didn't spend the next 5 years moaning about it. There will always be people too young at a particular ballot. What's the difference?
1) This isn't a regular vote that can be reversed after a few years if it's not working out. You got to vote 5 years later, when will today's 20 year olds who just missed out get their chance to say how they feel about the shambles we're now in?
2) Younger people are far more negatively affected by this choice than the predominately older generations who voted for it.
3) When you vote in a general election, normally the opposition actually bother holding the government to account and even though the party you voted for may not have won overall, your voice can still be heard in parliament.
4) This is a significant change to the way the country operates, far bigger than the normal changes a general election would cause, especially when there's clearly no mandate for the agreement that May has negotiated.
5) Finally, there have been no attempts to build a consensus to mitigate any of the people who were unable to vote's concerns about the future. In fact, things have turned out far worse than the leave groups were proposing during the referendum campaign.