The FB/Yahoo/whoever lawyer would point out that there's no indication of any discrimination. Your only evidence is permissible under the stray remarks doctrine, promulgated by Justice O'Conner in the Supreme Court decision for Price Waterhouse v. Hopkins (1989). You have no evidence of them doing anything illegal.
Stray remarks "standing alone" are not sufficient prima facie evidence of age discrimination. Nor is not hiring someone who is a member of a protected class, without evidence that being in a protected class was a factor.
You can't make up a random conjecture about them violating the law and do discovery. You have to have some evidence first. Show me a court case which says otherwise. If it were true then there should be thousands of court cases, or an EEOC guideline, which discussed it. I quote instead from http://www.eeoc.gov/eeoc/litigation/briefs/fried.txt :
However, “[s]tray remarks, even if they occurred as plaintiff
claims, are not enough to satisfy the plaintiff’s burden of
proving pretext. Stray remarks alone do not create an issue of
material fact to defeat summary judgment.” Bunk v. General
Services Admin., 408 F. Supp. 2d 153, 158 (W.D.N.Y. 2006). See
also Shapiro v. N.Y. City Dep’t of Educ., 561 F. Supp. 2d 413, 424
(S.D.N.Y. 2008) (“[t]he stray remarks of a decision-maker,
without more, cannot prove a claim of employment
discrimination”). In this case, the single, isolated mention of
Fried’s age, the only such mention in the entire record,
cannot, standing alone, create an issue of material fact
sufficient to defeat summary judgment. This is especially true
given that State, by Fried’s own admission, qualified his
remark by asking “what if you get hit by a bus.”
Accordingly, unless other indicia of discrimination are
properly presented, see [Shapiro, 561 F. Supp. 2d at 424], this
comment alone is insufficient to sustain plaintiff’s burden of
proving pretext as a matter of law.
You have no other 'indicia of discrimination.' You have not demonstrated prima facie evidence.
If what you were saying were true then why did Reid in Reid v. Google have to take the case to the California Supreme Court?
Answer: because what you believe isn't actually true, and you don't understand the relevant case law.