No, I do not think that FB coin will be any threat to Bitcoin. Most likely, on the contrary, it will have a positive effect on the crypto market as a whole, as more people will begin to be interested in crypto currencies.
Once people will understand more about the project, they will realize it will not become a threat but instead a hep to help bitcoin and the entire market crypto. We just think that Libra is adding value to the market, the problem with some people are just so dumb enough to make easy conclusion even without researching first on what Libra can bring to the market, they think anything that would come would be a threat.