Illegal suggests.....illegal. That's it Illegitimate suggests something altogether more vague...not quite right, morally...perhaps fixable...can be legitimate? ILLEGITIMATE - not authorized by the law; not in accordance with accepted standards or rules. "defending workers against illegitimate managerial practices" ILLEGAL - contrary to or forbidden by law, especially criminal law. "illegal drugs"
U.S. defense contractor accused of copying secret military documents (Reuters)
from the article: After uproar, Netanyahu orders stop to West Bank housing tenders