We have actually looked into that matter.
First, I should point out that this provision applies only to convictions for that specific offence. If an individual has already been convicted of a past offence under the Excise Act, 2001, the offence in question would not be punishable by the minimum sentence.
Second, we have noted that aboriginals were not especially involved in the traffic of tobacco, but rather in its production. So the offence we are discussing here is much less likely to affect them than those individuals involved in trafficking activities.
Third, as you noted, the Gladue ruling is an interpretation of provisions under subsection 718.2(e) of the Criminal Code. However, since those provisions were adopted by Parliament, I think that Parliament is free to change their interpretation.
This is not the first time minimum sentences have been proposed, as in Bill C-10. To my knowledge, the imposing of minimum penalties has never been challenged on the pretext that those penalties could have a negative impact on the interpretation made in the Gladue ruling.