What if, let's just make this hypothetical for a second, woman want men to stare at their breasts? Would you still have an issue?
Instead, let's dispense with the labels or making anyone out to be bad and simply think about our moms. There are countless things that are not sexist or wrong in any capacity, whatsoever. You still wouldn't feel comfortable doing them around your mom.
If it would feel awkward around your mom, then it might not be appropriate for a lot of wider audiences. Especially where we are potentially involving a professional capacity.
Edit: oh wait... You're saying that maybe the guys in the presentation are not reducing women to their physical bits, but actually treating them as human beings who like being treated this way? If so there is a simple way to disprove it: The women can't say "no". Since the women are not given any agency, they are not being treated as human beings but as mere objects with no control over how their bodies are used.
Or some men who believed it was offensive, belittling, discouraging or isolating to women. Like myself and a bunch of others.
There is a whole spectrum out there. The word "nigger" is a term of endearment for many.