Yep, I fully agree. At the tail end of Sarek's life we learn he loved Spock. He doesn't tell or show Spock ever, which would qualify him as a terrible parent by human standards but he's a Vulcan so maybe that's not how he should be judged. What Sarek also doesn't do is end his feud with Spock which I think is a perfectly good standard on which to judge a Vulcan parent. So while I love Sarek as a character he's a bad dad.