Okay, they're getting the same treatment as pigeons. By that logic you could also say they're getting the same treatment as all other humans, since the spikes do not distinguish between homeless and non-homeless people in performing their task.

It's also worth differentiating public and private uses of these methods (for instance, city-funded public spaces vs. private areas where sleeping should obviously not be allowed, like in the photo you linked). I can't blame an establishment for treating the symptom rather than solving the larger problem.