M doesn't stand for mature as in deep and meaningful content tackling the big issues of life, love and death. It just means content that is violent, offensive and sexual, which might be handled maturely or in a very immature way, but which would normally not be considered as suitable material for a person under 17 or 18 years of age. I typically avoid most games at that level especially ones that are very sexual in nature because it seems many such games do handle that content in an immature way. Whereas T rated games are typically more nuanced in how adult content is conveyed. There are exceptions of course and some M games have a great impact and the impact would be lessened if they were moderated down to a T rating.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
