Here's the thing, this is a movement that goes against public health recommendations designed to blunt the spread of a deadly disease. Their MOU is totally unrealistic, and is calling for the democratically elected government to be overthrown. What started off as a protest against have transborder truckers be vaxxed so to avoid quarantine was misguided....since the US was enforcing a similar rule. So, even if Ottawa wanted to change this, this small group of truckers would still be ineligible to cross.
Then, there are their tactics. Blocking roads/highways and honking all the time in residential zones is not really a great way to win support. People are angry about a lot of things the government does. It doesn't give them the right to do things like this. I can almost guarantee you that many of the people supporting these protests were calling from the RCMP to crack skulls when the First Nations blockaded rail lines and highways.
So, I don't think the PM has a responsibility to speak with them. He doesn't have a responsibility to speak with BLM protesters either. But there is a difference between them that you likely won't agree with. BLM is talking about historic issues where POC communities have been marginalized because of the colour of their skin. Truckers are just facing the consequences for decisions they made.