I'm guilty of this as well. I hated Apple for the longest time and for no other reason than they were different. I wanted nothing more than Apple to fail. Now I can't live without my iPhone and Mac and likely will never own anything else. I don't want to text people unless the texts are blue. I agree with the comments above about people and change. A lot of people don't like change. I'm the same way.
I have a somewhat similar perspective, but the difference is that I was (and still am) a huge fan of Apple products, and I simultaneously
hated Steve Jobs.
My observation is that people who hate Tesla tend to have that hatred focused around Elon Musk. They hate what they see as his bragging (example: that Model S/X are the best cars/crossovers), alleged disrespect for the older automakers, and over-promising on everything from delivery numbers to shipping dates. Tesla haters tend to characterize the company as a "scam" and a "cult".
Some of these aspects were why I disliked Steve Jobs. Jobs had a tendency to brag that Apple's hardware and software was the best. Some of Apple's demonstrations, like the 1984 Macintosh reveal, were a bit rigged (the Mac in that event was specially configured to speak). In the late 90's, I would grind my teeth when Steve Jobs bragged about how fast Apple's PowerPC products were, and how great MacOS was. I knew that was a load of crap, because anyone doing "real work" at the time (my narrow conception of "real work" 20 years ago) was using a Sun SPARCstation and later some variant of a Sun UltraSPARC, or an equivalent workstation from HP or Silicon Graphics. I had Apple using friends who mindlessly yammered on about the greatness of PowerPC, the "Supercomputer" Altivec chips, blah blah blah. Meanwhile, I was doing work on a computer with a "real" operating system (Solaris), and I knew that MacOS was a kludgy mess of holdover code from the 80's layered with all kinds of hacks and extensions.
Despite all of this... I had a PowerMac at home. It was friendly in a way that the UltraSPARC was not. For word processing, old LucasArts games, and surfing WWW 1.0, the Mac was fun. I could easily forgive its quirks and occasional crashy-ness. I could justify to myself owning Apple product because I liked Steve Wozniak and felt that he was an honest guy with a creative sense of humor.
I believe that 90% of the hatred towards Tesla is because many people find Elon Musk to be "arrogant", "weird", and "untrustworthy". The remaining 10% or so hate Tesla because they are scared of Electric Cars and the future in general.
Why did I dislike Jobs, but not Musk? To be honest, Musk seems like a lot less of a jerk, and Musk is also completely unafraid to admit, in public, when he has made mistakes (such as the Model X being too complex, and moving to fast with automation on the Model 3 line). Steve Jobs would just snap at people and say unhelpful things, like "you're holding it wrong" when iPhone 4 had issues with dropped calls when held a certain way.