The team wore those t-shirts AFTER Suarez was investigated and banned. To wear the t-shirts was an act of defending Suarez' words/actions, because that is how it was perceived, even if the intent was to support the man. If Firmino was found guilty after the Holgate accusation, I would be disgusted if this current squad wore such shirts.

Virtue signalling is the conspicuous expression of moral values.

Carra is signalling to the footballing world that he thinks that defending racism is unacceptable. If you're uncomfortable with this, with people condemning racism and highlighting that racist incidents cannot be defended, then you need to be honest with yourself about why. What is it about Carra's apology riles you up?