"we don't like" is quite so pessimistic,

it's more of a matter of preferences.

with the differences of cultures, traditions and way of living of Filipinos from other nationalities, it's just like logical to opt for flatmates with same level of bearing.

we couldn't say that we're far better to live with and have more proper and cleaner surroundings because all of us deal with various things.

i used to live with my colleagues in an accommodation and they are Indians, and their cuisine may not that good smelling to Filipinos, but they as well, hated dried fish we Filipinos cook, so it's like vise-versa.
one scenario too, when our team was invited in some festival of the Pakistanis, and they live in one accommodation too, and you'll see how neat they keep their compound.

so, i don't want to sound hypocrite here, but i am just speaking as one of the Filipinos, we just prefer living with our fellow country men (kabayan) for convenience; like some posters have said.

we need not adjust more to the lifestyle of other nationalities nor force ourselves to adapt to a different etiquette and manner of living.

so the next time you see those signs, put yourselves into our shoes. :)