Barely legal implies they were recently illegal. Nearly illegal implies that they will soon be illegal. I don't know the max age for concent, but being with someone that far outside my age doesn't really interest me.
Edit: thought about this more.....
It's illegal to fuck a corpse.... the people on the right are almost dead.
I definitely don't want to fuck someone to death.
I feel like consent from someone suffering dementia would have the same problem as consent from someone who is completely shit-faced drunk, making it not really consent.
I remember reading a while ago about a case where basically that exact thing happened. A guy got prosecuted for relations with his wife of a long time because even though they had been together for a ton of years, she had dementia and therefore couldn't consent. I'm not sure how it played out, but chargers were filed at minimum.
Don't think some people are interpreting this comic in the way that it's intended, given the title of "marketing matters". They're saying "barely legal" = "almost illegal", just phrased differently. Some of these comments seem to be reading it like the right sign is "almost legal" which would be a very different thing.