Ah, cornies, Gotta love 'em. High light exposure is to avoided just on general principles, but it is more specific to beer. The isomerized bittering resins in beer react with light to produce mercaptans, the skunky compounds that Americans mistake for an "imported flavor" and don't recognize as a defect. (Heineken wants so badly to show off its beautiful color and clarity that it uses those green bottles which don't resist the wavelengths of light that cause this reaction. Clear-bottle McBeers like Miller or Corona go to some expense to use an isomerized hop extract that is less susceptible to this natural process for the same reasons.... It's actually the same molecule that skunks use on your dog. Since meads lack these compounds (unless you add hops, and boil them a lot), it's not anywhere near as big a concern.
Oxidation, on the other hand, comes from oxygen meeting your mead after the yeast are no longer working (live, active yeast will take up and use O2 to an extent). This can be from aeration/splashing during racking or bottling, or to a lesser degree from not having the carboy topped up adequately during bulk aging. Oxidation can be insidious, as it can alter flavor in subtle ways while being shy of the classic "wet cardboard" or "sherry" tastes/aromas. Lesser oxidation can dull aromas and flavors, darken a mead (this is one reason commercial white wines are more heavily sulfited than reds, sulfite is a potent antioxidant), or in small amounts add to its complexity. This is one of the reasons some prefer natural corks over synthetics... they allow gradual oxidation through the bark for "big" meads that'll benefit from externded aging. Wooden barrels, in addition to lending some of their direct flavors, are used also for the gradual oxidation and resulting maturation that they afford.
Really I think the deliberate oxidation benefits meads a lot less than the big red wines we think of with barrel aging. Oxidation interacts with the tannins a good bit to soften and mellow them. For example letting a wine "breathe" means not just pulling the cork but decanting it into a glass or another vessel for serving; this allows O2 to meet the whole wine and also helps disperse gasses (like sulfite and CO2) in the wine. Ever notice how dramatically a wine changes over the first hour (or even few minutes) after you pour? Some of that's oxidation and especially helpful for young tannic reds. A well-aged, softer red can taste to me a little less interesting if allowed to breathe too enthusiastically. Really attentive tasters will notice a difference just in the time it takes to drink a glass, though much of that is dissipation of volatile aromas too.
I should point out that I'm NOT a serious wine guy! I'm all about an unpretentious, even gulpable table mead and wine and not anal-yzing my beverages, but the geeky technical stuff interests me a lot. I try to learn everything I can, use what I care to, and save the rest for that night your brother-in-law's co-worker wants to use wine to distinguish himself from the unwashed working-class stiffs. At our local homebrew shop, customers fall into camps of "winemakers" and "winers" along these same lines. I take a little guilty pleasure in laying in the weeds for that snobby guy so I can get in with "interestingly, that a common misconception." Does that make me a bad person?
Short answer for my money: worry more about sanitation and oxidation than light-struck mead.
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in Lyons, CO