Saying there are no other animals in the building is not a reason – it’s a simple statement of fact.
If the owners in this building felt strongly that they didn’t want pets in the building they could and should have passed a by-law to that effect. Any reasonable person viewing their by-laws before purchase would assume that pets were allowed, not that they weren’t.
You need to write to your EC and say that they are in breach of their own by-law by unreasonably refusing permission and therefore their decision is invalid.
Tell them that you are prepared to make sure the cat is not a nuisance to other owners and does not damage or stray on to common property. However, failure to provide you with written permission will force you to take them to the CTTT to get an order compelling them to abide by their own by-laws which say they must not unreasonably refuse permission.
I would do this promptly before you discover there is a rush to change the by-laws.
You’ll find the process of getting an order at the CTTT explained HERE . Don’t worry that this is about taking complaints about by-law breaches .. the process and, indeed, the forms are the same. Just scroll down to the section about CTTT orders.
The first part of the process is that you will have to go to mediation and it really should be resolved at that stage.
Your biggest problem is that the by-laws also say that you can’t bring a pet into the building without written permission – but if you have the cat already, I would just wing it and hope for the best. One breach of by-law doesn’t cancel out another but you are the one who’s being denied your rights.
If the EC can’t be bothered to read their own by-laws and understand the implications of them, it’s hardly your fault.