Why would you get flamed?
They're different organisations with different aims and objections. It's obvious you'll choose the one that most matches your own interests. Of course there's nothing stopping anyone from joining both.
The CTC also have regional/area groups that meet up (usually at weekends) for leisure/touring rides. You don't need to be a member to go on a ride with them - they only expect you to join if you're going to be a regular. Try a search for a club in your area. They are also heavily involved in York Cycle Show/Rally every year. This is a kind of bike festival with camping, CTC organised social rides, audaxes, trade stands, bike test riding (including folders, recumbents, 'special' bikes, tandems, trikes etc, if you've ever fancied a go on one) vintage cycling films, grass track racing and cycle polo to watch.
My advice is join.Iwas the secretary of my works team.The first thing i did was affiliated us with the ctc.Now my wife and children are members on the family ticket.You never know when you might need some help.