Maybe Medanore's 'Righteousness' saw through Tokugawa's potential, and kept his desire to play tennis because the former knew he has the potential to defeat him someday? Kinda like how Toguro kept sparing Yusuke's life and went through all the hoops and hassle to bring out his 110% (Yu Yu...
I think it's fine. I was entertained with how the other double players won without Howling, i. e. Tanegashima/Akaya vs. Bismarck/Siegfried. It proves that Howling is not as OP as compared to how Pinnacle of Perfection was shown in OG POT and early NPOT.