Obama and his umbrella holding Marines

[Thunderknuckles]

http://dailycaller.com/2013/05/16/ob...ella-protocol/

So Obama is giving an outdoor press conference with Turkey's PM. It starts to rain and he calls over a couple of marines to hold umbrellas over them to shield them from the rain.
It all made for some funny pictures but the linked article states that what Obama did was in violation of Marine Corps regulations. It seems like nitpicking but I became curious as to why male Marines are specifically not allowed to carry an umbrella while female marines can.

Any former Marines have an answer?