This is the key question - how did the African refugees enter Israel? Apparently, through the Sinai border. But there must have been considerable organisation on both sides to get them through what is usually an impregnable security zone. Obviously, if it was easy to just stroll across that border, then many Palestinian militants would have done so long since.
This whole topic is linked to organised crime networks, etc. There are people smuggling gangs in the Sinai, of Beduin ethnicity, and there are circles of privileged people in Israel who actually want a flow of refugees, for their cheap labour (the sex trade, also has been part of this. They were bringing girls from Eastern Europe and arranging crossing points at the border. Then, other refugees from Africa find out about this, and pay to go the same route.)
Once dumped at the border, the refugees are alone in a harsh environment, and tend to get picked up by Israeli border control. I have read interviews with some of them, which are rather touching - these are people who have suffered a lot. The reservists in the Israeli army usually treat them humanely, and give them water and rations, but they have no skills or resources to look after refugees. They simply ascertain that they are unarmed, and pass them on to the urban areas of Israel.
The mayor, interviewed here, might be criticised, but he does have a point. The govt of Israel is not providing for this sector - local authorities have to, and they themselves are not well off.
Very interesting info, thank you.