I think it's okay that parents can be interested in iCarly and they may like the relationship of Sam and Freddie. There's a difference between liking a relationship and shipping. I bet your parents don't go on Wiki, write fan fiction, find pictures. That's more shipping to me. But there's a difference if your parents say "Hey that Sam girl and that Freddie kid make a cute couple in that iCarly thing you watch"
iCarly can be for adults after all it is a family comedy show.
I write fan fiction, I find tons of Seddie pics. I go on Wiki I may be 19, but I'm also a mom, so I guess I can kinda see it from both perspectives, but I talk to my dad and my husband about why I like iCarly and Seddie. BTW They are both Spencer and Gibby fans.
Just saying I know I probably made myself sound like those creepy Twilight moms, but don't feel awkward if you talk to your parents about iCarly. My advice is as a parent, let your family know things you like, things you're interested in. It's nothing wrong if they can relate to or share those interests.
If you actually read my whole little spiel.. Comment, Give your opinions, stories, and how you feel if you find your parents like iCarly and Seddie