There's always 3 sides to a story: each party tells their part, and then there's what actually happened. I strongly doubt any leader in the CAF would deny bandaids, and the originally commenter made it sound like they were never able to go to CANEX and pick up basic stuff like bandaids, polysporin and second skin. Now I haven't been to the mega, but I would also suggest that it would be literally the only place in the CAF that doesn't have random First Aid Kits sitting around, especially at the Duty NCO's desk/office.
If people are hiding injuries so they don't go to the MIR, that's on them. The instructors are very much right in stating you need to decide whether you are "hurt or injured", and if your injury can wait 24 hours because you're going to miss a critical class/test. You'll have to make these decisions on sometimes an hourly basis, and as a potential officer, make them for your troops throughout your career.
I'd suggest here that if you're scared that you won't have access to bandaids and are reconsidering going to BMOQ, then you are likely not going to be successful on the course when actual stressful situations are presented to you. Realistically what are the chances that a small cut that is being covered by a bandaid is going to get infected unless its on your foot? Probably super slim, unless you're a dirtbag who doesn't shower or wash up.
I will also state that although the candidates may feel like "there's no repercussions" for the instructors, the real truth is that those instructors are held to an impossibly high standard, and are held to account for each course failure as if it was their fault the candidate couldn't complete the test/standard/etc.