You must be a old man like me with a attitude problem ,
Old is relative.
But I did do a 13 week unit on oils , lubricants etc so have enough knowledge to make a reasonable assmenent of oils
And I do fix mowers for a living
And I am on a lot of forums & groups cars, motorcycles & mower .
Like most things in life people argue most passionately about things than have the leas amount of knowledge about and in many cases that is limited to what they see on TV adds.
SO suddenly they can do no maintenance but use a really expensive oil and that will make their car / boat / motorcycle / lawnmower last forever, produce more power and use less fuel.
Mower oils are made for mowers so funny enough they ae then 100% absolute best thing for a mower.
After that air cooled engine oils , which are also died pink.
From then on it makes absolutely no difference which oil you use .
Because f the low volume used there are not many blenders who blend mower oil.
SO branded oil will be made by the same blenders as unbranded oil .
Now it might have a slightly different addative package but I have not seen any difference .
Most car oils now have no zinc which is not as big a problem with a mower wear wise as the cam loadings are quite small but it does make a difference to the anti- corrosion properties .
So Briggs oil , Kohler oil , Stens oil, Rotary oil will not make a tinkers cures of a difference to your mower.
IT is all in your head and if it makes you feel good then that is less destructive than a shot of booze or puff of wacky tobaccie .