If widipedia is asking me to donate to support it, but most of the money isn't going to support wikipedia, then that is a bit deceptive. It's especially deceptive when that money isn't just going to the wikimedia foundation's other projects, but as grants to a variety of other organizations that have very different missions.
I think much of the criticism of SeRCH is valid. Their "signature program" hasn't released a video in over 5 years and none ever got over a thousand views. The unclearly related "Vanguard Stem" (I think it is a parent or partner organization) hasn't put out video in over a year. To be clear, a quick google isn't enough to write this organization off, but it did fail to find any information that made SeRCH seem like a legit organization to fund.