Legal discrimination can occur in explicit, discrete instances, such as your example about this particular man. Illegal discrimination can, too. But illegal discrimination can also occur in a systemic, implicit way.

Systemic bias exists. One manifestation of that in this industry is the signaling in certain job descriptions and hiring practices. We needn't point to explicit, specific examples (e.g. "hiring manager told me point-blank 'sorry, we do not hire people over 30'") to see a broader effect.