Indeed, they shouldn't do away with moments of silence.
I assume you are referring to Wallace vs Jaffree?
However, there are problems with relying the Wallace vs Jaffree, partly because other cases were amalgamated into it and it addressed Alabama laws allowing a moment of silence, voluntary prayer, AND teacher led prayer. So it was not a ruling solely on moments of silence.
Moreover, in Wallace vs Jaffree the Supreme Court was essentially ruling against the faulty reasoning of the Federal District Court. The Federal District Court actually had the audacity to claim that the Establishment Clause did not prohibit state officials from establishing a religion!!!!!! So the ruling of the Supreme Court is not surprising. But the ruling definitely over-stepped its bounds when it said that all laws must have a secular purpose. Laws which uphold Free Exercise of religion are constitutional and do not serve an obvious secular purpose. So it is not just a poor test; it is a bad test.
Yet, even so, yoga does have a secular purpose. So HB 235 even passes this test!
As for the Alabama House vote, you said, "let it be the result of the State of Alabama voting." Well... they have! I think the addition of yoga will meet little resistance in becoming law. Do you think someone will try to take it to the courts?
In mean time, if you are worried that yoga is from Satan, then you better avoid stretching your arms in the morning when you wake up! Because, the "Hindu gods" are watching and they will be very pleased if you stretch your arms.
It is known.