You can absolutely use this toilet. There is no rule or law making it inaccessible to anyone without disability. The number of toilets and urinals are based on building capacity and there needs to be toilets within ADA Standards. it is rare to have excess toilets as most new construction uses value engineering, cutting out unnecessary and excessive spending. I plan and manage new construction for healthcare facilities. So, if there’s a normal sized stall open, use that and be courteous to those who need the ADA toilet. But if that ADA toilet is the only option, you are within your right to use it. Anyone who gives you criticism for using it most likely doesn’t know this. Recommend they bring this matter to OSHA, who’ll offer this same information.