In the news

He was arrested for inciting racial hatred which was based on a number of subsequent tweets which where racially charged in nature and included one where he blanket referred to muslims as "towelheads".

From what you report, it looks like a section 5 offence, at worst.

Aroogah nailed it.

Nobody has any right to not be insulted by anyone, even by racists and bigots.
Nobody was being discriminated against - insofar as discrimination is defined as being illegal or unlawful
Nobody seems to have been abused, other than in a general sense, and general untargeted abuse is, as far as I know, not illegal, other than from a section 5 public order offence perspective, and not from a moral perspective.

Without knowing the full context, it's probably best not to make a call though., I guess.