You are grossly misrepresenting the situation and what your own link says. If wages + tips don't equal the normal minimum wage of $7.25, the employer is required to make up the difference.
They get, at worst, normal minimum wage.
They get, at worst, normal minimum wage.
US Federal law states minimum wage is only $2.13/hr for someone that makes $30/month in tips (instead of normal minimum $7.25) [1]. If they don't make $30 in tips the employer must make up the difference.
At 30 hours/week (and 4.3 weeks/month), $30/month works out to $0.23/hr, so the effective minimum wage is still only $2.36/hr.
Some states are quite a bit higher (eg Hawaii is $7/hr), and in some (eg, Alaska, California) the minimum wage is the same regardless of tips.
[1]: https://en.wikipedia.org/wiki/Tipped_wage_in_the_United_Stat...