I think Gastineau's issue isn't the record being broken but how it was broken. Imagine if someone ties Brees' 54 consecutive TD pass record and in the 55th game, game practically decided, the opposing team lays down and let's the QB "throw" a touchdown because they are cool with him or friends. As Saints fans, I think we all would be annoyed to see our guy lose his record like that. If it's broken, fine, but you would like to see it happen within the competitive framework of the sport. I couldn't imagine Ohtani sitting on 73 homers and in his last at bat of the season getting a changeup down the middle of the plate to "break" the record.
That record was probably a source of financial income in addition to pride for Mark. I get his emotional response to being hurt about it.