Injuries making it difficult to walk sometimes result in people using tools to assist them in getting around after the injury. In some places it isn't uncommon to find wheelchairs and electric scooters provided by stores for use by the elderly and others who have trouble walking or being on their feet for extended periods. I sustained injuries that result in instability while walking and standing at times, and stairs are one of my worst enemies. I don't use a wheelchair, or show any sign of these injuries (until I fall down for seemingly no reason, as observed by onlookers...or the noises my legs make, especially while going up stairs). I know others have been criticised or called lazy due to similar injuries when they opt for an elevator instead of taking stairs.
Sure, she may be standing up from the wheelchair to get a happy drink, but it is kinda messed up to try to make a joke out of someone without knowing the details. Maybe we should accept peoples differences.