I'm not sure how making excuses would justify racism in response. It doesn't follow especially after considering that your reasoning would mean that the response isn't directed at the person actually making the "excuse".

Nope just leftists of all flavour's like to talk about oppression, poverty, discrimination etc.

So leftists just come into threads about black people committing crime and spontaneously start talking about oppression in response to the thread? Proof?
To me it looks like the racism generally comes well before any supposed excuses are made.