Reason Number One:
The obvious reason why you should hate captcha entering projects is that: All captcha related jobs involve spamming work. Spamming is a crime and we should all condemn this act. Say no to spam no matter how much money you are offered.
This work should simply be called as “Spam Jobs”.
Reason Number Two:
The second reason is that: One can only make few cents via doing this kind of work for several hours.
Pay for such job is like few cents per hour. How can anyone agree to work for this kind of rates? This is like working for FREE.
Reason Number Three:
People who agree to do captcha entering jobs are the ones who get scammed by buyers in many different ways. Buyers who open captcha projects are mostly scammers. They will not pay users for the Spamming work they do for them.
Most buyers will just vanish after the spam work is complete.
Reason Number Four:
As mentioned in the third reason most of these buyers do not pay users for doing captcha projects: so if a service providers do not gets money for a project than he will not get any ratings too.
Rating is everything at freelance sites. Without ratings, one cannot get work for good rates.
New comers should remember that: in the beginning, they need to earn ratings not money. Unfortunately, many new comers do the opposite and they decide to do anything [any job] to earn money [and not ratings]. Such new comers often do captcha jobs and in the end, they get no money, no rating and get scammed and aslo get banned by the freelance site.
Reason Number Five:
Captcha jobs require service providers to harm other websites. Doing such warm is wrong in many ways: it is a crime and is wrong ethically.
This work can involve making thousands of accounts at different websites like Gmail, Yahoo Mail, MySpace etc. Making accounts in such number is not allowed by these sites. Harming other websites is a bad thing to do: It is a cyber crime.