Universal design is the ultimate type of inclusiveness. It accommodates virtually any physical needs and a person's size, stature, intellect, or ability. If a product or design fails to be usable by someone that it seems should be able to use it, then it fails the universal design test and should not have the universal design label applied to it.
A great way to determine if a product or feature truly is universal design is to ask a simple question - is anyone excluded from using it because of how it is designed, of where it might be located, or how much effort or manual dexterity it might take to use it? A similar question to ask is how it looks - does it stand out where it is located as being something special or not really fitting into the overall design scheme but looking like a specific treatment?
Not every product or building feature or characteristic is going to be universally designed. If we wanted to achieve this concept, we would have to condemn the majority of the homes in this country - any home with a step or grade change of any type into the home (not to mention multiple steps or a series of them), bathtubs that aren't accessible, windows that can't be accessed or operated, poorly illuminated rooms, loose or slippery flooring, or many other features that might work for one age group, ability level, or physical height.
Some homes are going to be located in neighborhoods or areas where there is an architectural integrity to preserve that precludes any type of step modification anyway. For these, other treatments such as elevators can be a universal design solution. Elevators do fit our criteria that they can accommodate anyone. It's just that they don't align with everyone's budget and they don't apply to single-level homes without a basement.
For those homes where we can achieve universal design solutions, however, the issue is to create equal access to what we are including. Take a taller toilet (19" or so - often referred to as comfort height). Is this universal design? In a word, no. It often is labeled as such, but it clearly does not work well for children and smaller adults (people under 5' 6" or those with shorter legs). While they might be able to actually use such as toilet, it is not comfortable or particularly safe so it is not recommended for shorter individuals.
Another common solution is raising the height of the automatic dishwasher, thinking that this would accommodate wheelchair users better than a traditionally installed lower unit. In reality, the higher installation makes it more difficult for wheelchair users, and it looks out of place in the kitchen because the countertop has a distinct interruption (and raised as well) rather than being continuous. People with stiff backs or those with other issues that don't allow them to bend or lean over easily may find the raised dishwasher beneficial.
We must be more careful in what we call universal design to make sure that they really are features that anyone living in a dwelling - or coming onto it as a guest or visitor - can use. Otherwise, it is a different type of design or strategy such as aging in place and not intended to accommodate anyone but just the specific needs of the occupants of a particular home.