Of course there are different qualities of toilet paper. In a commodity-style market for toilet paper there would be competition on both price and on quality axes and there would likely be multiple points of equilibrium between quality and price.
People choose to differentiate by superficial brand identity specifically because it creates the experience they want: reproducible access to consistently acceptable quality.
Their only selling point is a certain mid-market bling. No one making a rational decision would ever buy one.
But this is basic US MBA strategy. Cut corners on tangibles, replace them with hype and marketing bullshit targeted at a specific demographic, then leverage The Brand™ to charge the highest possible prices.
Use both formal traditional advertising and informal online astroturfing to maintain the illusion of value.
It's called marketing, but in reality it's industrial-scale behaviour modification.
But we use a lot of different manufactured goods in our daily lives today, many manufactured in ways that require expert knowledge to appraise. It's unreasonable to ask for the average person to be well-versed in them all.
The fact that consumers aren't very discerning is exactly created by brands -- they have learned to discern based on identity instead of by quality, because brand recognition is less effort than material inspection.
Additionally, a brand certainly does not provide the attachment to consequence that you claim, once a brand has consumers' loyalty and a sizable market share it can adjust quality with relative impunity.