https://www.cbc.ca/news/politics/garneau-boeing-ethiopia-crash-1.5054234 Canada had to be dragged kicking and screaming to do the right thing in my opinion. Many third world countries were leading on this issue.
It might help to know what actually caused this Ethiopian crash. Do we know? Have the voice and data recorders been downloaded? The only information that I've seen concerns the Lion Air crash in Indonesia which apparently involved the flight control system's anti-stall provisions. Several other pilots have reported having to turn it off to regain control of their airplanes. But... as far as I know, we don't know if that this had anything to do with the Ethiopian crash. Witnesses in Ethiopia describe the airplane making loud sounds and trailing smoke before it crashed. That suggests a different sort of problem. It sounds to me (a layman) like an engine compressor stall or surge. (That's just speculation.) https://www.skybrary.aero/index.php/Compressor_Stall The loss of an engine might conceivably have led to a loss of airspeed that triggered the anti-stall automatic control system that forced the plane's nose down. (That's just speculation.) And consternation attending the loss of an engine and perhaps inadequate training caused the pilots to fail to take action necessary to recover control of the aircraft. (That's speculation too.) That might constitute an explanation that combines an engine fault (itself with many different possible explanations from a manufacturing defect to improper maintenance), a badly designed automatic control system and pilot error. It's just speculation though, without data from the recorders. I don't want to assign blame to anyone specifically (plane manufacturer, airline pilots and aircraft maintenance, engine manufacturer and maintenance) until I see some better facts. I can't blame the various aviation authorities for grounding the planes in the absence of facts. (Abundance of caution.) But I don't want to start criticizing the Canadians or the Americans for being slower than other countries that simply jumped to conclusions.
So far, it's believed the planes had the same issue. https://finance.yahoo.com/news/u-reverses-course-ground-boeing-183931746.html
There were many discussions in Canada by experts for and against grounding. However, the general consensus in Canada is that the 737 max is a new type of planes. By piggybacking on the 737 model there were financial gains to be had at the expense of due diligence and public safety to the public. I do not understand the argument, but corporate greed seems to be at its roots.