They might not be club types. The autism comments annoys me too, just because some kids are less social than others it certainly does not mean autism.
I hated clubs as a kid. I hated all clubs, youth clubs, after school clubs, holiday clubs anything which was an enforced group of other children. I was part of a gymnastics club, I was very good at it, several other girls in my school/local area went but I hated going. I was a shy child and clubs gave me a school-like feeling and I certainly wouldnt have taken part at all if my mother was watching. My sister was a tomboy, was much more outgoing than I was, she was in a football club and also karate, she would go to the local youth club too (me and my brother never ever stepped foot inside). She signed herself up for things such as day trips ran by the local church for the kids. I remember only going to one with her which was to a roller disco and when we got there, for some reason unknown to me, refused to do it and sat on the sidelines watching everyone else, just wanting the time to hurry up so we could go back home. Any opportunity she did clubs, including a home work club for ESL children - baring in mind we are English.
With my own kids, my eldest chose Tae Kwondo and joined Minecraft and cooking clubs himself. He did Tae Kwondo for around 2 years (he is now 14 and in police cadets -suggested by the police as a result from him having mild but frequent brushes with the law) I didnt even attend his exams as I learnt from experience he did alot better getting involved if I wasn't there. While he was attending these, I took him and another of my kids to a free Krav Maga session, where the parents had to sit in rows of chairs watching, which I shuddered at on behalf of the kids. My eldest despite being a seasoned club goer point blank refused to get involved, started acting unusually infantile and clingy, then spent the rest of the time sat with me, while his younger brother got stuck right in, happy as Larry. I let them choose. My youngest lost interest in clubs soon after and that was OK, he is an incredibly talented footballer but has never wanted to take it further than the school team despite alot of encouragement from his PE teacher. However once he reached 10, he wanted to do boxing, off his own back. I definately feel they should take the lead, but it is worth giving it a go again, without you watching perhaps. If they still dont join in, I wouldnt force it any further.