If clicking a comment just opens a small textbox beneath the comment then it's not a big deal if they miss. But I can definitely see having different pages loaded being a problem.
But ultimately, it should not be a limitation of the technology that determines what is an isn't usable. That's a job for UX designer, and they should have every freedom with the technology to create their designs.
Although I agree that it would be best for an UX designer to make such decisions, most of the time one is not involved and there has to be some sort of limit based on some standard. If you allow potentially bad decisions, then ultimately a great deal of bad decisions will be made. For example, look at how browsers will render absolutely awful HTML soup and the state of most of the HTML out there.
But ultimately, it should not be a limitation of the technology that determines what is an isn't usable. That's a job for UX designer, and they should have every freedom with the technology to create their designs.