Often the app in questions is designed for a specific platfom and is only used for that platform. For this reason zoom is unnessescary, and often annoying for the end user. E.g. when creating a mobile app, it is expected that this will be used on a mobile phone, and therefore the text size etc. is selected for this specific purpose. When selecting something from a dropdown or combobox on a mobile app, the app often zooms by itself, and for some reason it is hard to zoom out.
For this reason, a settings feature for the developer should be created, where the option to disable zoom for end users is available.