In light of everything that's happened this week, I think the first tweet could easily be interpreted as having been intended to further stoke his followers' outrage. The 2nd tweet, while somewhat factual, I think also came off as incendiary and divisive. What excuse does he have at this point for not attending the inauguration other than to make yet another spiteful statement to increase tensions and, therefore, incite more violence?

The full comments in the post detail similar reasoning.

Update: As many people have pointed out (and as the Twitter post mentions), the 2nd tweet could also be interpreted as emphasizing that it would be safe to commit further violence at an event that he won't be attending. This is certainly a much more grave concern than the one I mentioned above.