Perhaps.
But probably not. It was probably the father of the 7 year old child sitting at the table nearby giving him the "stink eye" just like the OP thought.
And you're missing the bigger point here. You sit down at a table with someone elses child sitting nearby. You don't know them, you haven't asked for their permission to vape around their child. Is that EVER an appropriate time to break out the ecig and blow clouds?
This "blow clouds" mindset bothers me. When I vape, the most obvious tell it that I have something up to my mouth. My device doesn't provide "clouds" and I certainly exhale in a way that is as discreet as possible. Think Tootle Puffer x 100.