1) There are many Russians in South America. Hence there is a Church to serve them.
2) Our Lord commands us to evangelize the world so it would be against his command to not evangelize. Proselytism on the other hand would be defined as any type of unfair evangelism, such as bread for the Gospel (paying someone off with food or money), or lying to them, or attacking practicing Catholics. There are plenty of non-practicing people of Catholic descent in Uruguay, just like there are plenty of non-practicing people of Orthodox descent in Russia. According to such agreements, such people are fair game but not active believers.
3) The Catholics have plenty of churches in Russia, Greece, etc.