Yep goodberry is free healing. It was already excellent for that reason.I don't think this is the OP's issue. The druid is not going to cast goodberry instead of some other spell when healing is needed. At the end of the adventuring day, the druid can use any unused spell slots to cast goodberry before taking a long rest. With the goodberries lasting 24 hours, that's stocking up for the next day.
Also at issue is if the character wants to burn all of their spells slots the "long rest" before the night of a planned dungeon delve, stockpiling a huge amount.
With the life cleric ruling, it is broken - if you're using the slow healing rules. If you are using the standard full heal every long rest... well, you already heal so quickly, maybe it isnt such a problem.... but then ... maybe it still is, again coz it's a big bunch of free healing, undermining the resource management aspect of the game. Too much healing makes the game too easy/unfun.
I recommend ignoring that particular Sage Advice ruling. Not one of his best.