I would also add that that this was not the first time that Christ upset the apple cart by changing OT thinking. He worked on the Sabbath by doing good and healing on the Sabbath. There were Jews that took issue with that and didn’t follow Him, but He didn’t change the message.
So it is with Christ’s reference to drinking His blood: it too broke with tradition. In this instance He wasn’t merely talking about animal or human blood. He was talking about His Blood. Something new and entirely different.
And yes, some Jews couldn’t handle that either...and they too walked away.
But He didn’t change the message.
I think you are confusing ‘tradition’ with ‘law’.
The law said to keep the sabbath holy. Tradition dictated how the Jews thought that should be carried out - no healing.
It wasn’t a ‘tradition’ that said don’t drink blood, it was the law. Jesus came to fulfill the law, not to do away with it (Matthew 5:17&18).