Why does HK insist on continuing to use this flawed phrase?
1. Its ICAO. Whether you think its naff or not to follow ICAO, smarter people than you and me have deliberted on the subject for decades and still come to the conclusion that inclusion of the word "to" in the standard phraseology is recommended. If you know your standard phraseologies then there can be no confusion. A quick glance shows that even NavCanada's (where you state you are from) standard phraseology includes the word "to".
2. I'm not aware of anywhere that has a transition level above 29,000 ft, so, as BuzzBox points out, any reasonable pilot would expect to hear "Climb to
Flight Level Two Niner Zero if that was the case (with or without the "to" if you prefer).
3. On more than one occasion here in HK, we have had pilots take a descent clearance "Descend six thousand feet" as exactly that - and descended a difference of 6,000 ft from their previous altitude. Stupid people do stupid things. No matter how some try to remove the ambiguity someone will befuddle us.
Me thinks you are the dope who insists on it's use by HK controllers.
Please, you flatter me with your perception of my authority over other HK ATCOs.