Granted, I know nothing about Canadian law, but in the US I think prior bad acts can be used for certain purposes. Just for example, if something about lm's MO in this case was completely consistent with his MO in the case of prior bad acts. In that case I don't think it would be considered character evidence, but rather actual evidence that the crime committed in the same manner was likely committed by the same perp. I would imagine, but don't know for sure, that the rules would be similar in Canada since the underlying rationale would be the same -- that the evidence is actual proof that the crime was committed by the defendant rather than merely proof that the defendant is not a "nice" person.
I haven't seen the kitten vids so I don't know whether they are different in the sense that lm is clearly identifiable actually committing the acts on those vids. Or whether, as here, he deliberately did not show himself actually committing those acst as well.
jmo, though. Anyone who knows better please enlighten me