Who is Buddha?

A friend came across these phrases in a Buddhist website — ‘Who is Buddha?’ and ‘Buddha’s teachings’. He asked whether they ought to be ‘Who is the Buddha?’ and ‘The Buddha’s teachings’. He remarked that it’s ironical that such incorrect English is used very often in the West! I agree, because:

1. It’s wrong to skip ‘The’, as ‘The Buddha’ refers specifically to
Shakyamuni Buddha instead of other Buddhas.
2. Buddhists refer to ‘the Buddha’ as… well… ‘the Buddha’!
3. The title ‘Buddha’ by itself is somewhat disrespectful.
E.g. We say ‘the King’ instead of ‘King’.

(I like the installation art in the picture. Does it imply self-reflection?)