Yes, coercion of any kind is anti-capitalist, yet you advocate for coercion by the state.
No coercion (voluntary transaction, no state involvement):
"I'll sell you this widget, but only if you agree to bring it to me for any repairs." "Ok."
Coercion (state intervention):
"Hi, I see you are about to sell your widget to that other guy who would like to buy it, knowing only you can perform any future repairs. If you go ahead, I will use the full force of the justice system to punish you, up to and including death."
I realise this is unrealistically ideal. The language is very important to get right though. You are advocating for coercion for the common good, not the absence of it. The state is impotent without violence, you don't need to shy away from it. State == force.
No coercion (voluntary transaction, no state involvement): "I'll sell you this widget, but only if you agree to bring it to me for any repairs." "Ok."
Coercion (state intervention): "Hi, I see you are about to sell your widget to that other guy who would like to buy it, knowing only you can perform any future repairs. If you go ahead, I will use the full force of the justice system to punish you, up to and including death."
I realise this is unrealistically ideal. The language is very important to get right though. You are advocating for coercion for the common good, not the absence of it. The state is impotent without violence, you don't need to shy away from it. State == force.