I consider this a perfectly valid point, actually. If crop circles are made by aliens (though of course I see no reason to believe they are), we're dealing with one or more species that probably evolved in a hugely different setting from us. I find it incredibly illogical to say things like "if they came here they would be intent on killing us", or "if they're so advanced they'd never resort to crop circles to communicate", thus judging everything they do or would do on how expect humans to do things.
Look at how differently species on Earth communicate. Case in point, canines greet each others by smelling each others' rears, and mark territory by urinating on rocks.
Well, no. Even being open minded at different ways of doing things, you can still have some basic expectations.
Like that such a species still must have a way of communicating fast enough. Whether it's by sounds, linking antennae and using smells, flashes of light, EM radiation, or really whatever. You expect them to be able to at least say "ok, I wanna make a big rocket. I can haz cash grant?" in real time, without having to drag everyone to some place with tall grass to trample in some Hello Kitty shape.
Really, there's a fine line between not expecting them to be exactly like humans, and pretending that any magical BS is as likely.
The comparison with dogs is also basically invalid.
For a start we're talking about a pretty dumb species. In neurons per input, humans are at 20, dogs are at 4. (Cats are at 5.) Virtually any quick rule of thumb we thought of, be it brain mass per body mass, brain surface per body mass, etc, dogs rate as pretty damned dumb. And you don't even have to go that far to notice that dogs never built rockets.
And it's not as much of a greeting as just a species that's got a good sense of smell, just sniffing each other's smell.
Sniffing butts isn't a particularly good form of communication, and even dogs don't use it for any kind of real communication. You couldn't have a civilization that teaches each other maths and astrophysics to build a rocket, by sniffing each other's one single scent gland.
From a species that's managed to build a technology far in advanced of ours, build a spaceship, and get all the way here, it's actually very justified to expect a more advanced form of communication than sniffing and going "oh, it's Hans".