it is a big world out there. Like some people swear by WD40 as chain cleaner & lube, some others wouldn't even touch it.
It is generally accepted that modern car engine oil are not suitable for wet clutch motorcycles. A- high revs will cause more foaming B- friction modifiers will affect clutch operation C- the extreme shearing & pressures the gear box generates
I have read some people claim to use car oil without any so called problem. Off course the final choice is up to the owner. It is their bike & their money & if they like to experiment, why not.
I only use full synthetic in my car (since 1980!!) & bikes the prices I get are almost the same to within a couple of pound.

Hope you are enjoying your bike in this nice weather