Many famous contributors to Athenian culture and Hellenic history--like the philosopher Aristotle and the painter Polygnotos--were not Athenian citizens. Many builders of temples, as well as some of the richest businessmen and women weren't Athenian citizens. Egyptians, Cypriots and Phoenicians, all came to Athens and founded their own districts, with temples in which they could pray to their own Gods. Xenophon, in the Constitution of the Athenians, states:
"For this reason we have set up equality between slaves and free men, and between metics and citizens. The city needs metics in view of the many different trades and the fleet. Accordingly, then, we have reasonably set up a similar equality also for the metics."
Outside of Athens, métiokos were not treated as equally. Of all the poleis, only Corinth had a decently seized population of métiokos. Their legal status is unknown, however. In Sparta and Crete, foreigners were hardly ever allowed to stay.
Back in Athens, métiokos, while welcomed, were disadvantaged from the get-go. They had to register their status within a month of arrival. They had no political influence, were not entitled to governmental aid in case of emergencies, the could own no farm land or real estate unless they were given special permission by the government, and they were not allowed to procure a contract with the government to work the mines. They were, however, expected to enter the army, and pay taxes if they were wealth enough, like citizens. On top of that, they also had to pay a métoikos poll tax--the metoikon--which was twelve drachmas ($ 720,-) a year for men and six for women, as well as another special tax--xenikon telos--if they wanted to set up a stall in the market place.
Like doûlos, métiokos did have access to the judicial system; they could both prosecute others and be prosecuted themselves. Unlike citizens and very much like slaves, métiokos were not allowed to represent themselves; they needed a citizen to vouch for them--a sponsor, called prostates. For a freed slave the sponsor was automatically his former owner. Métiokos were entitled to take part in religious ceremony. Like slaves but unlike citizens, métiokos could be made to undergo judicial torture. The penalties for killing a métiokos were not as severe as for killing a citizen. Although doûlos could become métiokos, it was fairly easy for métiokos to become doûlos; a failure to pay the metoikon tax, not finding a citizen sponsor, causing trouble, marrying a citizen or claiming to be a citizen themselves could all cost them their status.
The term 'métiokos' began to lose its distinctive legal status in fourth century BC, when métiokos were allowed to act in the court without a prostates, and came to an end in Athens, when the purchase of citizenship became very frequent. Until that time, citizenship was a guarded treasure. While citizens, métiokos and doûlos were indistinguishable in appearance and behavior, society functioned largely on their separation.
Xenophobia is a dislike or fear of people from other countries or of that which is foreign or strange. While it may seem that the ancient Hellens weren't xenophobic, they did have an extreme urge to merge the foreign with the local. While doing that, they kept the locals firmly protected in a privileged bracket of society. Xenia was a sacred duty, as well as a sacred right, and it applied to citizens, doûlos and métiokos alike. Politics, protection and judicial rights, however, were entirely different matters, and if you weren't born into citizenship, attaining these rights was virtually impossible.