Is the Hadith: "Whatever of this money comes to you while you are neither covetous nor a beggar, take it; and that which does not, do not pursue it with your soul," to be taken literally? And is refraining from taking money or food that is permissible for the general public, on the pretext that it did not "come" directly to me, considered an act of extremism?

It is permissible for a Muslim to take money that comes to him without asking. As for what people ask him for, or what he covets from their wealth, he should not take it except out of necessity. This is due to the corruption it entails, including: the heart becoming attached to creation, its being a means of wrongfully acquiring wealth, increased attachment of the soul to this worldly life, and the lack of blessing in this money.

There appears to be no harm in taking donated food and drink, as long as it is taken in the manner specified by the donor, or according to the condition stipulated in his endowment. Similarly, there is no harm in accepting a general invitation for iftar (breaking the fast) in mosques.

However, if a person can suffice himself with his own food and the earnings of his own hand, that is better, and he is not to be blamed for it. In fact, abstention is always مطلوب (desirable), especially for one who is self-sufficient and has what covers his needs.