Because you misunderstand that both religion and biology can be studied with scientific principles, still.
I have always been upfront that I don’t have qualifications in biology in university or college, where I can work as a biologist.
In my computer science, it is void of any study relating to biology.
In civil engineering, I had subjects on soil mechanics and engineering materials.
Soil may often have bacteria or have organic matters that may increase the salt levels or acidity levels that cause problems to foundations to buildings or it may corrode pipes.
In engineering materials, it is the study of what materials could be used in construction, eg concrete, steel, etc, but among the materials could be used are woods. So I would have to know physical properties about woods, such as how would woods handle stresses when load are applied to it, to test its compression strength (eg if the wood is being used as a pillar), or to test its tensile strength (eg if the wood is being used as a beam); what types of wood to be consider in the design or construction, eg softwood vs hardwood, seasoned wood vs unseasoned wood, etc.
Just because I know some things about woods, for engineering design purposes, don’t make expert in tree or in dendrology.
The little biology I did learn here, only concerns with designs of large buildings, public construction, designs of road and highways; designs of dams, of reservoirs, or of pipe systems for water supply (eg water mains) or for drainage (eg storm water systems, sewage systems.
The points being that my studies (subjects) may involve in some limited knowledge in biology, but it only give me qualification in engineering, not qualifications in biology. I don’t become a qualified biologist.
I also had geology subject in civil engineering course, where I need to be identified rocks that I may encounter during excavation for building foundations, or stone being used as materials in construction (eg granite, marble, basalt, etc), but that don’t make me a qualified geologist.
Just because you may have degrees in religion, and may have study a couple of biology subjects, don’t make you a qualified biologist.
I cannot get a job as a biologist, but can you?
Have you ever worked as a biologist after your degree in religion?