why do I have to take the IELTS

that is the burden we Filipinos face when we apply for a visa or to travel to NZ since I applied for work or migrating to that beautiful place that I very much love to be for a very long time now as I have worked and experienced other cultural traditions in other countries aside from my native land the Philippines,I never had a hard time understanding other languages that I've encountered as working in the middle east countries and in the Caribbean where I work with different nationalities and it never came to my mind that it hard to relate to others but it came to pass we all and I for one understand in good relationship working and adjusting other traditions but never with how they speak what matters is being a friend and a co worker,respecting others and the place that I am staying obeying what are the laws and staying away from any trouble or problems that might come and the issue here and my question is "why should I have to take the IELTS" can I not understand what NZ people are talking about or how they speak their language, so if they come to our country they too should take Filipino test too if they can speak and understand even other nationalities.