AH does it really matter? I mean Bach and some old timers thought it terrible to compose using the piano - term was Knights of the Keyboard (a pun of course of the many hnights belaboring over a piano keyboard to grasp blindly at something to compose).
Many composers relied on algorithms (a set of procedures) to compose and that is why you have stylistic periods. Tell your teacher he or she is a not very smart unless by a crutch she or he means you are mistaking the sound of the "virtual" instruments for real ones - well yes then she is or he is correct.
Oh and ask your teacher this - what would she say about someone who says has written many great works (whatever that means) using the computer, a figure from piano improv or from a violin, and sheer musical daydreaming? Has the work suddenly devalued because of the means used? To me that is like saying if you were using a newly invented form of steel which offered benefits never before had but you refuse to use it because it may become a "crutch". To carry this metaphor further, the steel still has to be molded by you - no matter what you use.
Honestly, sometimes music teachers can make the whole act of compositional creation utterly overly difficult or complicated. You should ask YOUR teacher not to use paper and pencil , nor piano , and write something with the computer. Wonder if he or she could even create a decent composition - because that is the fallacy of her argument - the premise is assumed that software music notation automatically carries a high risk of writing bad music for some vague reason it is a crutch - well I IV V I, I II6 V7 - I and a whole host of harmonic templates (as well as species counterpoint) are "crutches" we rely to create what is considered "good" music. With this in mind, why not ask your teacher to write music with NO crutches - no harmonic template is to be suggested at all, no contrapuntal rules are to be suggested, and his or her crutch of piano or pen and paper abandoned.
Once again the only time computer software is faulty is if you mistake the virtual sounds and performance for real sound produced by humans.