The peak in 2017/18 was not that unusual al though granted, higher than it's been for a while. Nevertheless it was still a strain of influenza coupled with the particularly cold weather so a known quantity.
The current situation is down to a novel virus with no effective vaccine as yet. We are in uncharted territory and as such life has to step away from normality to deal with it. Like it or not, the most effective way of stopping viral spread is isolation. Huge chunks of the population have demonstrated their unwillingness to comply with even the most simple of guidance so we find ourselves in the current situation. Have the government handled it well? Of course not, but I very much doubt that ANY political party would be handling it well without the general consensus of the population and if this country has proven ANYTHING over the last few months it's that there IS no consensus among the general public, most of whom seem to lack even the most basic of common sense.
As for Manchester, it all just looks like political point scoring at the cost of the people of Manchester. Somehow if Corbyn or Starner were in power I doubt very much that Burnham would be kicking up as much fuss even if presented with the exact same scenario.