My underlying issue with the mechanism here is the use of affirmative defenses from

"Organizations (broadly defined under the Criminal Code) can rely on three potential defences:

The organization instituted a “prescribed age-verification method” to limit access. It would be up to the government to determine what methods qualify with due regard for reliability and privacy. There is a major global business of vendors that sell these technologies and who are vocal proponents of this kind of legislation.
The organization can make the case that there is “legitimate purpose related to science, medicine, education or the arts.”
The organization took steps required to limit access after having received a notification from the enforcement agency (likely the CRTC)."

(not quoted due to long lines and lack of line-wrapping in preformatted blocks)

Affirmative defenses shift the burden of proof from the accuser to the accused. The accuser does not have to prove that the accused didn't implement age-verification, or that the use was not educational.

The accuser only has to prove the presence of nude imagery (which is easy), and the accused then has to generate a case on how their age-verification is sufficient or their usage is educational (which is hard).

The burden of proof and work required thereby, rests almost entirely on the accused. The balance of effort required is heavily skewed.

It would also prevent any attempts to get a summary judgement prior to the trial, at least in the US. In the US, a summary judgement is only possible when the facts don't support the case. I.e. if we presume everything the plaintiff claims is true, it's still not a violation of the law.

Imagine someone says that you wearing purple was an assault on them; you could likely get a summary judgement because even if you were wearing purple and that caused them some trauma, it doesn't rise to the legal level of assault. The facts are irrelevant, because the entire case is wrong.

That doesn't work here, because the only thing the law cares about is whether nude imagery exists. In order to assert an affirmative defense you have to launch a defense, which requires a trial. There is no earlier point where you could say "hey, we're clearly a sex education site because x, y and z".

Imagine a sex education website. They very likely have indisputable nude content on their site. They're now in a situation where anyone in the country can meet a very low cost bar (find a nude image), and cause them to have to mount a difficult and expensive defense (prove one of the affirmative defenses at trial). The law doesn't require the plaintiff to prove or even identify the affirmative defenses that don't apply.

This law would be much better if the burden of proving that provider did not implement age verification, has not resolved any issues pointed out, and is not educational fell on the plaintiff. Summary judgements could be back in play; the judge could look at the evidence and say "even if I assume what you're saying is true, that doesn't prove the site isn't educational" and toss the case before the defendant has to build a whole case.

In my greater opinion, I don't think children accessing sexual content is a big enough issue to shift the burden of proof onto the defendant. I think ideally children wouldn't be exposed to pornography until they're old enough to contextualize the content into a coherent world view (e.g. the BDSM community takes a lot of care around consent and emotional well being that is sometimes not obvious from pornography tailored to the market). That being said, I think the "damage" done by seeing it earlier than one should is too low to justify this dramatic of a response.