The modern automobile is safer, cleaner, more efficient, and more technologically advanced than anything that came before it. Yet those improvements have come at a cost. For many owners, mechanics, and independent repair shops, that cost is repairability.
Who is there to agree with - the car is my property. All they own is the copyright to distribute copies of the software. Imagine a disclaimer on the front page of your copy of Fifty Shades of Grey.
Their legal claim will be the bullshit 1201 of the DMCA preventing you from breaking a digital lock on your own property to “rip out that first page”.