Yes; if you go out thinking, "I don't have to care about the condition of my bike or what to do if it breaks down because there are bus routes along the way, or I can call a friend," then you're not a serious cyclist.
Using your logic, I must not be a serious driver because I don't drive with the equipment necessary to repair my car. Or my bike, when I am riding. Or my e-bike when I am riding that.
Folks who are serious about any hobby or activity are also often relentlessly practical. I used to ride 100km from the city I lived in, out to my brothers farm. It was not a particularly long or challenging ride, and it had cell service most of the way, even 20 years ago. I always did a gear check, and carried spare tires, but in 4 years of doing that 20-30 times per year, I replaced tires, but never a chain on that ride. I also never carried the tools to do that work because it fell into the category of unnecessary gear. If there was a problem, I was only about a 30 minute wait for help from either side if I needed to be picked up.
I also used to do a fair bit of trail riding, and for a much longer period of time, and for significantly technical trails. Again, a gear check ahead of time, and proper maintenance meant I took tubes, but not the chain repair tools (and one time I regretted not taking 4 tubes, because it was a long and hot 14km hike back carrying my bike on a July afternoon).
I am not going to gatekeep your ability to gatekeep, but you should at least understand that your perspective on what constitutes a "serious" cyclist is completely subjective and not rooted in anything meaningful.
Pretend instead of “serious” they said “frobnozz”. You’re not a frobnozz cyclist unless you can do a handstand on your handlebars! How absolutely un-frobnozz can you get??
There’s a tendency to ascribe value to words like “serious” but it’s a temptation, nothing more. Who cares that some bozo thinks “serious” drivers drive manual transmission cars, or ride bikes in a particular way.
