Yes; sure.

But you don't own (for example) Netflix. So Netflix can exclude you if you use your computer in certain ways, right?

i.e. if you refuse to use a secure boot infrastructure and do remote attestation of the trust chain to Netflix, they can refuse to provide you service - obviously based on the assumption that this was all made clear to when you signed up.

The 'ole "they're a private business, they can do what they want" defense.

I try not to whip that out because it's all fun and cool til they do somethimg you don"t like.