[2020] a piontless question but i'm still curious

All of the previous answers are all kinda-almost correct.

The red cross on a white background is a trademark protected by the Geneva Convention, and is a symbol of the Red Cross. A generic red cross, on some other or no other background element, is not trademarked. There are some other symbols on a white background that are trademarked too, such as the Red Crescent symbol.

The Red Cross is not a medical organization—this is a common misconception because of certain aspects of the Red Cross, in addition to how the trademark is often violated and the symbol is mistakenly used by unaffiliated medical organizations—but rather an international humanitarian organization.

The trademark is enforced. Regardless: even if a trademark isn't enforced against every violation, that doesn't make the use lawful.

The medkit, suturekit, and health status bar were not in violation of the trademark. The first two were white crosses on a red background, while the lattermost had no background element at all. All three of these icons were changed for consistency with the other icons that had been changed. A mix-match of different symbols for similar game content would be confusing.