And I'm sure there's no shortage of characters that would be willing to try! But first we have to get them a'venturin' somehow.
And yeah most of the backlash would come from the Hudvalr side. Still workshopping this idea, so let me know what you think, but since dragons are natural walking magic batteries, their ambient aura also tends to make things around them go very screwy and sorta ignore the laws of reality because MagicTM, hence in the past they were treated as something akin to mobile, everpresent natural disasters. Blizzards would rage around dragons with an ice-affinity, lava would eventually erupt and bubble around a fire dragons, torrential storms would follow water dragons, things of that like. Because of that, people from across the land were always really interested in finding out ways to get rid of dragons in any way possible, Hudvalr and probably Qaeltine included.
Until someone in Hudvalr discovered that living creatures of any type could form a pact or bond with a dragon, their natural calamitous leakage of Very Bad Stuff lessened greatly. The creatures in question had to be capable of channeling all that excess energy when bonding with a dragon or else they'd probably explode or something, but in return they'd get some neat benefits which led to fantastical stories of a white deer that can grant wishes, or mountain goats that created mountains and valleys by eating all the surrounding land. This led to an even greater interest in hunting down dragons because even if the dragons themselves were less of a threat, the creatures they bonded to were often just as worse, if not even more so, than a regular calamitous dragon.
On a side note, I had the idea that maybe dragons had to go through this bonding process as part of their maturation stage, which made me snicker thinking that all these calamities were happening because of really horny dragons bonding only because they wanted to bone other dragons. I mean, maybe mating for two fire-type dragons wouldn't be an issue, but it'd be mighty awkward if a fire-type and ice-type wanted to get together but couldn't get around the whole I-literally-melt-you-with-my-presence type deal.
Anyway, somebody eventually had the bright idea of gasp "what if humans could bond to dragons too?" And then one fantasy novel series later, we have the present day relationship of Hudvalr royalty and dragons.
Naturally bonded humans also got some neat benefits too, usually in the way of unusual features and amplification of natural magical prowess which meant that dragon bonding was typically reserved only for royalty, those of really high status, and fanciful tales consisting of the adventures of farmboys/gals and their new dragon friends. However, the last bit is generally seen as a a bit blasphemous mainly due to influences of the first two leading to certain ideas of racial purity and powerful bloodlines, and so the idea of anyone from Qaeltine bonding to a dragon would be seen by a fair few number of people as a huge No-No.
Didn't expect to write that much, but TL;DR: Qaeltines bonding with dragons is a huge cultural and militaristic taboo because a lot of Hudvalri are racist, aristocratic dicks
EDIT: Ah, and the reason it's a militaristic taboo is because even after bonding, dragons still emit ambient magical auras that can fuel spells around them, thus allowing magic to be cast in areas where normally it'd be magically void or deficient