"heroes and martyrs" is the English translation of 英雄烈士, which is not a generic term of praise in Chinese but specifically applies to someone who died in battle (or some similar act of bravery) — think acts worthy of Victoria Cross in UK or Purple Heart in US. Even people who worship Mao do not think of him as one of the "heroes and martyrs".

In China you certainly can point out, even criticize, Mao's role in the Great Leap Forward. Even "Official History" criticizes Mao! You can't be too "over the top" about it, such as comparing him to Hitler or accuse him of being a mass murderer, lest you get cancelled. But the reason you can't has nothing to do with the draft laws being proposed here.