

Discrimination in hiring happens every day. Be it conscious or subconscious. If there isn’t a hard, unavoidable quota no one can force anyone to hire people they don’t like. The laws may just forbid them from being this forthright.
Never attribute to malice what you can more appropriately attribute to stupidity. The people who coded this may be young and not even on their first divorce yet. To me, that’s what this family plan business falls under. To leap from that to organized discrimination of folks being born out of wedlock seems a tad too conspiratorial from my POV.
This may be a fryable fish. Yet I see much bigger fish elsewhere.
What may also hold back development of functional patchwork family plans is legal hot water. Not every split is amicable. The Googles and Microsofts may simply have decided they don’t want to be put in a situation where they need to adjudicate between two warring ex partners whose bitterness is overriding their child rearing responsibilities with petty disputes. And building a system where maybe new partners can gain access - even just by mistake - to their spouse’s kids accounts also has very bad PR potential when it turns out the step parent is abusive.
Nevertheless you should let them know about your feedback. Patchwork families are quite common and they can probably do more in that area.
What’s wrong with these people? The rabbi had time to sink to the floor, the priest is clearly passed out on the floor, why is the pastor still walking into the bar? Are they all blind and deaf?
The deeper message must be that just out of shot an imam and a Buddhist monk are looking at each other puzzled exchanging remarks like “They really cannot learn from each other, can they.”
(I do get the bar joke, internet. No need to well actually me. This was very much tongue in cheek.)