We develop names for things, ideas, places, etc. based on everyday observations or easily associated ideas.
For instance, among Filipinos it is common to hear people call cameras as "kodak" after the popular film brand and toothpastes "colgate" again after a brand.
I think the British call their underground train system the "tube" because the tunnel reminds them of a tube. They call elevators "lift" because the contraption could literally lift one from floor to floor. I'm sure you can think of more examples.
Unfortunately, the so-called negative connotations to the word "Filipina" were derived in the same way. People from different parts of the world associate Filipino women to the profession they are commonly known to have.
Throughout Asia, Europe, and the Middle East the most common profession of Filipino women is that of a nanny or "domestic helpers" as some would put it.
Even if the number of female nurses who work abroad is growing (concentrated in the UK, US, Canada and Australia) their presence simply do not compare to the nannies. Moreover, I know how people overseas would look down at the nursing profession as a "glorified nanny" in the hospital despite the years and money spent in college. Doctors are still respected but nurses are looked down upon.
However, the word "Filipino" (pertaining to men from the Philippines) is associated to highly skilled people. Of course, the usual contact made by peoples of other nations are with male Filipinos with skills in technical fields.
What you should know is peoples from poorer countries/communities all over the world (except for some countries like Indonesia) would never allow their women to work abroad in fear of abuse no matter how poor they might be. They are very protective of their women believe me. This is why they wonder and have asked me on many occasions (I have worked in the Middle East) why we let our women work abroad as nannies and face humiliation and abuse.
As for mail order brides, combine facility in English with the notion of marrying a foreigner as the key to poverty alleviation and you will find many Filipino women in this wedding ring hunt. Actually, I know many who are successful in their professions who are very much into this. Check out the nearest internet cafe in your location and you might find some. And who are we to criticize them? Or put it this way, who are we to think that they are doing no good? These are adults who can decide for themselves. Believe me they enjoy it and they would talk you down if they sense you are belittling them.
And yet, we go back to the stereotypes associated to the word "Filipina". I realized that no street protest, publicity campaign, or even a hundred Leah Salongas or Cory Aquinos will change that. The image associated to the word "Filipina" was shaped by thousands of encounters back then and now, and perhaps in the future. Between the people you read in the news and the lady who cleans your house everyday who do you think will leave a longer lasting impression?