To say that “eruvin in general” rely on kulos is either ignorant or stupid.
I don’t feel the need to address the content of your post; I did that already.
I will address, however the tone and choice of terminology.
Why is it necessary to adopt a confrontational and degrading approach instead of carrying on a civil discussion? Please, if you disagree, present your arguments; explain why the kulos we mentioned are not really kulos. I’m ready to hear.