I've been at this drag racing thing a while, and I went through the same thing (doubters) with my 2010 Challenger R/T . I set the record for quickest naturally aspirated stock 5.7 engine Hemi back in 2011 and nobody has come close to it three years later. I did it through constant tinkering and weight reduction. If you want to be the quickest, there's more to it than simply showing up and running your car. Not everyone is willing to put in the time and effort to do what it takes to get there.
Same thing with the 14.55 in the Veloster. I can assure you that we have bought nothing for this car besides the 17" Motegi wheels and a set of Weathertech floor mats. We took out the passenger seat and the back seats. The gas tank was down to less than a 1/4 tank. The washer fluid was empty. The glove box and console were empty. We removed the foam block with jack and tools from the trunk. My wife is also pretty light as a driver. We dialed in tire pressures front and rear. We experimented with different launch techniques. Yes, it's an automatic. But still, you can stomp it from an idle, brake torque to 1000, 1500, 2000, etc. Each car on each track will require a different technique.
I provided both a time slip and a video. Not sure what else I can do. Instead of sitting on your couch calling me a liar, I suggest you spend some time figuring out why your car is not as quick as it should be.
