Ahhhhh, welcome to the world of condo associations. "Why" do they do many things? Because they can is sometimes the only logical answer.
With that said, condos prefer stable long term tenants vs transient passer-bys.
A condo association cannot vary the rules from owner to owner. Therefore, it's 1 lease per year. Just think, if there was a loophole (such as the tenant wasn't paying and had to be evicted, or they disappeared in the middle of the night, etc. etc.) - - - everyone would use that loophole to rent out for the season (which is exactly what associations do not want).
Associations cannot do for one and not the other. Believe me, there would be such lawsuits for discrimination if that would occur.
I hope you get your issues resolved, but for owners/buyers looking for "case by case" rules . . . condo associations are certainly not for you!
Lisa M. Brodeur
LMB Realty Corp d/b/a Alliance Realty