Why is sparkling wine usually a bad candidate for breathing?

Answer: Bubbles escape faster

Bubbles escape faster ✓ — Correct. The same air exposure that can open a young red gives dissolved carbon dioxide more chance to leave sparkling wine. Since bubbles are a core part of the texture and pleasure, breathing often spends the wine's special effect. There are niche exceptions, but for most sparkling bottles the better move is to keep the fizz.

Foam feels smoother — Not quite. Letting bubbles calm down can make a pour look less foamy, but it also removes what makes sparkling wine sparkling. Smoothness is not the only goal; the lively bead is part of the style. Treating fizz as a flaw mistakes the wine's feature for a problem.

Aromas need more oxygen — This is the common overgeneralization. Some still wines smell better after oxygen, but sparkling wine's show also depends on dissolved carbon dioxide. Extra air may release aroma, yet it also speeds the loss of fizz. For most bottles, the trade is not worth it.