I'm not defending this person or endorsing what they said (and have since doubled down on), because it was extremely crass and unnecessary.
However, on the general subject of tolerance that you raise, it brings to mind Karl Popper's paradox of tolerance, and the notion that unlimited tolerance should not be extended to those who are themselves intolerant. To do so only provides greater freedom for people to promote intolerant ideologies.
It's fair to say that many of the views that Widdecombe held could be considered intolerant. But those views should be opposed through reasoned argument and political discourse, rather than snidey personal attacks on someone who has been brutally murdered, and it's unfair to tar the entire 'tolerant left' with the same brush as this particularly hateful person.