Its really sad when cases like this make it to the appelate courts due to the bad facts. However, I would expect that HSLDA will probably try to take over the case for the sole reason of overturning the bad precedent that was set here. Yes, these people sound like they may have been lousy parents which may well be a matter for child services if they can actually prove abuse. However, a ruling that homeschooling is not legal is disastrous for good homeschooling families all across CA.
Of course, that's not what was ruled at all.
The decision affirms that you can't break the law to homeschool, but following the current law allows homeschooling.