Attacking by "Taking the high road"

Solution 1:

It's called paralipsis. It's when you draw attention to something by claiming to ignore it.

I'm not suggesting my opponent is a racist, but...

Solution 2:

You could classify this, potentially, as subterfuge:

Subterfuge:

an artifice or expedient used to evade a rule, escape a consequence, hide something, etc.

Which leads us to expose the meaning of artifice:

• clever trick or stratagem; a cunning, crafty device or expedient; wile.
• trickery; guile; craftiness.
• cunning; ingenuity; inventiveness: a drawing-room comedy crafted with artifice and elegance.

So that one might say:

His subterfuge led to the questioning of his opponents scruples.