england was proud of the fact they had become viewed by france and the rest of their european rival's as a country of brave fighting men.every man and young boy would know who all the champions/fighter were.young boys even collected trading cards that came with a fighters stats and an illustrated picture's.
At the time though only the wealthiest of men could afford proper one on one boxing lessons and inturn boxing become viewed as the gentleman's sport as so many upperlass men were taking part.
Other reasons are:
throughout history boxing become more and more a somewhat fair and less violent way to settle disputes.one on one, man to man and as equals men fight it out and would usually except the consequences if they lost.
It has always been less brutal than many other forms of combat and over the year has become a way to take part in fair and controlled violence.
Boxing has still maintained/developed some of it's gentleman/noble characteristics.
Men fight more as equals now than they ever did back then.Today we have fighters competing at the same weight,same rules.Stricter rules are now in place that see fighters can no longer get away with so much wrestling and fouling,hitting while down or half way up and brutal tactics in general.
Boxing is called the gentleman's sport because boxers basically just use their fists as weapon ( no elbows, no head butting ) and they fight erect and strictly above the ground. Boxers are also not allowed to hit their foe below the belt, on the nape or back of the head, after the break and when the opponent is already down on the floor.
That cannot be said of other fight sports, especially MMA.
Back in the days of yore in Merry old England Gentleman would meet tin the large entertainment rooms of games. Billiards, then perhaps, exercise with wooden exercise pins that they might swing around for strength. they might engage in wrestling and always foil or sword fighting skills were shown leading to fencing with epees,etc. Eventually leather mittens called mufflers became in style and gentlemen would toe the mark, a line drawn and engage in fisticuffs, (boxing). a gentleman's game until it became prize fighting.
Because the people are nice
Because they don't use no stinger no more.