People on all sides of the Political spectrum voted for 'Brexit'. The Government, led by Mrs May, now have a mandate, from the majority of those who voted, to extricate the peoples of these islands from the EU.
Remainers have a variety of concerns about our exit, how it will be achieved and what it will mean for us afterwards. These are, no doubt, sincerely held and have been given a great deal of consideration.
Brexiters, similarly, ought to be credited with having deliberated long and hard about the matter although having reached an different conclusion.
Those on 'the left' appear to be able to see absolutely no integrity in the manner in which our withdrawal is being/will be handled simply because it is a Tory administration in charge.
I doubt if a Labour-led withdrawal would have been satisfactory, either (not least because the implication is that there would never have been one because there would have been no In/Out referendum) because the Remainers want to Remain and anything else is unsatisfactory.