This is just the UCI being dumb about how they regulate their own sport. They published helmet guidelines last year, and the new Giro helmet ostensibly meets those guidelines. Now the UCI is going back and saying they need to take a closer look, because there’s an online kerfuffle about a new helmet - perhaps they should have done that last year? I get that people can be creative and bend the rules, but surely give this time?
Put in a body that reviews helmet guidelines every x number of years (2? 3?). This should include safety as well as size/fairing specifications. In the meantime, let anything that meets the criteria proceed, and fine helmets which don’t meet the guidelines. Review again in x years to see if your initial rules were creating the desired effect, and make subsequent rules take a certain time before the come into being, so if you change your guidelines, everyone knows 6 months or a year in advance. The only exception should be safety - if they find something unsafe, then you can convene a special task force to mandate safety features that come about.
Idk if the UCI has the leeway to regulate the sport with ever changing rulesets. There’s world tour teams with big budgets, but there’s also lower tier basically amateur events taking place under UCI rules as well. Having the helmet rules change every 2/3 years forces teams and riders to buy new helmets to meet the new regs. Imagine crashing and needing a new helmet on the last year before the reg change.