Because it is the manufacturers logo.
You're asking the wrong question, it is not "why do OpenPLi not implement their own logo", it is "why do other images feel the need to rub their pole so much"...
Yes very true. But once an owner (like myself) has flashed his VU+ with an other image other than OpenPli (which I have found to be very good and fast booting as well unlike the others i have tried)and afterwards opts to install OpenPli is not good for OpenPli itself to have another image's Splash screen together. My opinion. Thank you once again.