People who place photos on a resume are not a protected class. Perhaps it is a bit unusual to automatically exclude those applicants, but it is _not_ discrimination (as defined by the law).

People who ride their bike to work aren't a protected class, yet I've been informed it's not okay to ask a candidate how their commute was.

I really don't want anything to do with the recruiting and hiring process.

That sounds crazy. How is it not okay to ask about the commute?

Yeah I've never heard this. Frankly, it gives relevant info about how willing the candidate is to endure the commute. Plus, it's polite conversation. Also, bicyclists aren't a protected class.

Not the OP, but I expect it's more CYA. Many employers will reject a candidate that puts their age in their cover letter or resume. Rejecting these isn't about fighting age discrimination, but having the policy means that the candidate can't later claim discrimination, because anyone who shares that detail regardless of age is out.

Year of graduation, or years of experience, would surely indicate approximate age for the majority of candidates?

All hiring is discrimination, unless you hire every candidate (even if done randomly, it is discriminating based on the random process.)

What is going on here is discrimination on a (presumptively)[0] legal basis to avoid risk of discrimination on an illegal basis.

[0] there is some possibility of inadvertent illegal “adverse impact” discrimination here.