With regard to the speculation.... it's interesting that aircraft accidents, at least of high profile, are so infrequent that we almost seem to expect an 'extraordinary' explanation; we don't just 'expect them to happen' it seems.
Personally, without knowing the pilot at all, or anything except what's been stated generally, I would find the theory of a deliberate 'kamikaze' type crash incredible for a number of reasons.
- No-one has come forward to suggest the pilot was unstable, unwell, financially troubled or any of these 'markers' that typically come out after a 'suicide'
- There appears to be no explicit direct link between the pilot and the facility he hit, other than the fact that both were 'in aviation'
- To me the most telling: the aircraft is described as having had an engine failure. Not only are there plausible scenarios where this could have lead to loss of control, but as far as i can recall, no proven 'suicide' event has occurred other than with a fully operational aircraft. That's hardly a surprise - if you intend a dramatic 'end' then you don't need a failure, you already decided your course, and you don't need to induce a failure to provide an 'alibi'.