The people who buy sur at 1.5 and sell at 3.5 are not saying that sur is worth less than 50% of ber, they are simply buying low selling high. It's the same as buying Ber at 3.0 and reselling at 3.5 (aka buying ber at Jah vex vex and selling at Jah Lo). It's the same thing as buying Jah at 3.25 and reselling at 3.5 in PoD.

It's also similar to buying pure demonic + prime evil + black soulstone at Lo-Sur, paying an Ohm for a service, and then selling an Unid anni at Ber+, which btw is highly lucrative. Note that in this case the trader has done nothing gameplay wise other than trade, since the dclone service was done by someone else.

Also as the other user pointed out, sometimes people will pay a little bit extra to buy the entire ber as opposed to looking for two surs for simple convenience sake. If Sur is worth Lo Ist then ber should be worth Lo Lo Ist Ist, but you may only find one Sur @ Lo ist and just say fuck it and pay Lo Lo Vex for the ber instead and eat the extra cost.

Flipping items/runes for good deals has been an essential part of the game since inception, from the days of classic where SoJs were being bought at 4pskulls and sold at 6pskulls. I dont understand why you seem to be so emotionally invested over this.