Yes, you're overreacting.
...and you diminish a very important protection mechanism with banal nonsense !
In fact employers are free to chose their employees' suitable qualifications and personalities as they please and they deem fitting into their company.
Discrimination is to reject because of race, gender, religion, age etc.
Check antidiscrimination laws in your country, you won't find video games in the list...
I do agree though, it is not the smartest decision to include that.
It's not even required for the job, just for the one hiring to have someone like minded to hang out with.
One could argue however it is to build a certain company climate, which is fine to do nonetheless.
I don't see the post age discriminatory either.
A) growing up around the times of SNES is just a BONUS
B) hiring someone for example in a senior capacity with X years experience, thus excluding a certain age group (young), is perfectly legal and not discrimination at all.
Age discrimination would be if a young and old person fit the job description criteria and they hire the young person, "because young".
Please check the following U.S. law for further details:
Big thanks to Richard U for providing the link!
§623. Prohibition of age discrimination
(a) Employer practices
It shall be unlawful for an employer—
(1) to fail or refuse to hire [...]
any individual[...]because of such individual's age;
(f) Lawful practices; age an occupational qualification;
other reasonable factors; laws of foreign workplace;
seniority system; employee benefit plans;
discharge or discipline for good cause
It shall not be unlawful [...]—
(1) to take any action otherwise prohibited[...]
where age is a bona fide occupational qualification
reasonably necessary to the normal operation[...]
or where the differentiation is based on
reasonable factors other than age[...]
or where such practices involve an employee
in a workplace in a foreign country, and compliance
[...]would cause[...]to violate the
laws of the country in which such workplace is located;
Keep in mind, other countries will have different laws...