Of course Twitter couldn't do the football referee thing of an 'accumulation of offences' as that would leave them open to all kinds of attack, so instead they have chosen to latch on to some tweets that his base can easily argue are harmless just because they happen to be timely in coinciding with him doing something legitimately illegal.
They really fucked themselves over by continuing to let him gradually up the ante without properly stepping up.
Even if this won't convince the die-hards, Trump and the Republican Party must be bleeding casual voters right now.