I could learn to be a hairdresser. Yes, I could. I might not end up a top stylist but I absolutely, definitively could learn to cut hair to a decent standard.
Yes, I could. Yes, I know this for a fact based on reality and my own experiences.
It's not looking down on the job to say it's just an everyday, ordinary job. I don't look down on anybody who works for a living, all work has dignity.
I could not learn to be an electrician, a builder, or a plumber. I might manage to be a painter though again it is an incredibly taxing physical job.
Hairdressing is not an equivalent to those jobs they are much (much) more physically taxing and require a lot of stamina.
Electrician training involves electrical theory, maths, code compliance, blueprint reading and safety training to prevent lethal errors. Plastering and bricklaying require precise calculations for materials and mixes, structural alignment, load bearing knowledge, and handling heavy physical setups.
Plumbing requires in depth knowledge of pipe systems, water pressure, drainage and gas lines and in many cases building codes blueprint reading maths for calculations and strict safety protocols to avoid leaks, contamination explosions or structural damage.
Hairdressing centers on artistic techniques like cutting, colouring, and styling, with far lower technical or safety thresholds.
What would I do without a hair stylist? Cut my own hair. I have and often do and particularly since discovering the unicorn technique, and I've been using Schwarzkopf wash in wash out colours for years. What would I do without a plumber or an electrician? Possibly die, or lose my home or live with an unbearable problem. The stakes are not the same.
You're not hearing disrespect to hairdressers, it's just indifference.
And it's not a British attitude it's the attitude of the commenter you replied to.