The disection IME takes place as a response to the excessive adulation and worship given to a newly member of the deceased. Take Princess Diana for example - there were calls to have her beatified. Such calls are far more disrespectful to the memory of the person than pointing out that they were human with problems.

I have respect - but I have respect for people as people. De-humanising them is far worse than pointing out their flaws as well as their virtues IMO (and I won't say after death anything I wouldn't say in life). Mourn honestly and I'll leave you to it. When the hysteria takes hold, I'm going to give you the equivalent of a slap to try and break you out of it.

As for Thatcher, I believe she was a necessary counterbalance to politics that had swung too far - but the person who reintroduced rickets to the inner cities even before she became PM went on for far too long and caused as much damage as she fixed.