I think that it's all in the eye of the beholder as cliche as it may sound. I mean really if you have a bond with a pet (whether," love" is in the equation or not), there is obviously some kind of connection. How do you define that? If they prefer to come to you over someone else, if they are just chilling in their cage and you put your hand in and they crawl on to be held, if you are holding them and they just remain calm in your hands and relax in a comfortable position, if they curiously look upon you while you hold them jutting their body out putting their face closer to yours. I mean, maybe these aren't "feelings" per say, but they are obviously evoking some sort of thought process as to, "I have a connection with this individual, or I think of them as a caregiver." Obviously not in those words. But, if they are able to make that connection, which I believe whole heartily that they are based on my experiences, then I think they are completely capable of, "feelings".
That being said, why is someone in a white coat who sits in a lab and is taught to be critical and use scientific approaches to finding meaning in things better to judge this than people who spend years with the hobby? Yes, they may find the answer based compiling data and scientific logic (which is claimed to be, "fact"), but I think they miss a lot of the stuff we are able to catch based on hundreds to thousands of exposures and situations. Sure, we attach feelings because we want to and care about our pets, but I still think we are just as qualified as hobbyists to come to our own conclusions and back them with evidence.
Just my two cents.