Okay, as much as I like the Changelings, I do have a problem or two with the way they're interpreted by some in the fandom. I have no qualms about them being portrayed as more sympathetic and not uniformly evil (the latter I actually advocate), but I keep seeing their actions being justified (like most MLP villains) to the point they are portrayed as victims, not wrong in itself, but a lot of fans begin to take this as fanon, or canon, or whatever it's classified as. I have a problem with this, because I cannot agree, no matter how much I like Changelings, that they were any way in the right in what they did in Canterlot Wedding. Also, my other gripe is how fans justification of their actions sometimes leads to making the heros out to be selfish and in the wrong. Celestia, of course, has been on the receiving end of that most of all, just like with Luna and Discord.
I'm going to look at the issue and give my own take on it.
Okay, so on one hand, the Changelings' primary food is emotion, namely love, which is the argument many use when making the Changelings sympathetic and trying to justify their actions. Feeding on other sentient creatures is more of a necessity than a desire, although the soldiers did visually take enjoyment in their invasion of Canterlot. In this point of view, the Changelings are just trying to prevent themselves from starving, making it a predator and prey situation, which then does not make the Changelings exactly evil. Even with Chrysalis, the point can be argued she was fulfilling her duties as queen to find love for them to feed on.
With this in mind, it is perfectly understandable for people to sympathize with the Changelings. But then some people make out the ponies to be selfish jerks, Celestia especially, for the Changelings being expelled from Canterlot. A lot of fans seem to forget things from the ponies' side. Remember the predator-prey situation I just mentioned? Well, as the prey, Shining Armor and Cadance were simply both defending not just themselves, but their people as a whole, when they cast that spell to repel Chrysalis and the Changelings. It's like what Celestia and Luna did with Discord - they were saving their people. I mean, what do we expect the ponies to do? Just lay down and let the Changelings suck them dry? I mean, yeah, it's how they eat, but it is still wrong. This is kind of the problem, as one member whose name I have forgotten mentioned in one of my precious topics on Changelings, said about the two species living in peace. They basically cannot do that as the Changelings needs will have to be placed above the ponies, and the latter at the end of the day would just be cattle to them.
As for Chrysalis, whilst it is noble to find your subjects good, it should be pointed out that she mentioned it almost offhandedly like some minor side-note, and she did not even try to use it to justify herself. Her personality has to be kept in mind. She definitely took sadistic pleasure, like her soldiers, in all the grief and suffering she inflicted on the ponies. It was pretty obvious she had more selfish, imperialistic motivations other than just finding food. I mean, yeah, her subjects get food, she gets to take over Canterlot and soon, an entire nation!
This is just my take on the matter. The Changelings may have been searching for food, but they were still the ones in the wrong in Canterlot Wedding and the ponies shouldn't be faulted for just defending themselves from an invasion that would have spelt doom for their people. I look at the Changelings and see a complicated situation, not victims of the "tyrant" Celestia.
If you have different views on the issue, please post them and discuss.