It's a building with more than one level. Therefore making it inaccessible easily for a while host of the population.
By adding a lift for those with disability you aren't making the building 'accessible'. You are in fact actively discriminating against a whole host of the population with other accessible needs.
I know many buildings where there is more than one floor, they have lifts - for anyone that needs the accessibility feature.
Most have signs asking for you to prioritise those with disability, young children and/or a buggy.
What drives me nuts is the members of the population who don't prioritise those people. Not with parents who have a toddler and pram who don't try and bump them down the stairs, whilst carrying baby in a long and holding on to a toddler. Why would any decent human being think this situation preferable to using a lift? It's actually quite dangerous. (And yes people use to do it blah blah blah but why do something dangerous when it's unnecessary).
I remember visiting a Woolworths when ds was a toddler, they had an escalator upstairs to the children department and cafe, which you couldn't take buggies on. And stairs. I asked if I could use the lift because I had a shoulder injury and couldn't carry buggy and get ds up stairs. Nope. I asked if someone would take ds or buggy for me. Nope.
So I bought my stuff in BHS and ate in the cafe there 
Not everybody fits in a neat little box and everyone's needs vary. Making everything accessible to all is the only way forward. I truely believe by making such a song and dance about some things being solely for use of those with a disability your still separating this population out as being 'different' - exactly the opposite of what disability groups are campaigning for. No parent of a child, child or adult I know with a disability that would prevent them from using stairs would ever think it was acceptable for adults to be bumping pushchairs down stairs when a lift is available.
I also think there needs to be more facilities available for those in wheelchairs, such as toilets with hoists, in many more public spaces, shopping centres, leisure facilities, museums etc.
So I don't think you are BU.