He is still the pope and people shouldn't blow this whole thing out of proportion; it is something for the clergy to discuss among themselves and with pope Francis before reaching any firm conclusions about it.

There are four different issues here: 1: whether the event affects papal infallibility; 2: whether Francis has fallen into heresy; 3: whether a Pope falling into heresy loses automatically his office; 4: whether the Church can depose a Pope who has publicly fallen into heresy.

1. Francis has stated that his endorsement of the radical (actually straightforward) interpretation of AL is authentic magisterium. Now, authentic does not imply definitive/infallible. In fact, most authentic magisterium - either from Popes or from Ecumenical Councils - is NOT definitive/infallible, and there is a clear example of authentic erroneous magisterium being later corrected: the teaching in the Decree for the Armenians of the Ecumenical Council of Florence on the matter of the sacrament of sacred orders, later corrected by Pius XII in his 1947 Apostolic Constitution Sacramentum Ordinis, this time by a definitive pronouncement.

Bottom line, this event poses no problem for the doctrine of papal infallibility. This doctrine concerns only ex cathedra definitions, which have very strict requirements. So, there is no problem with Francis being the legitimate Pope on these grounds.

2. Quoting from an interview to Fr. Jean-Michel Gleize, an SSPX priest who has written a long study on issue 4:

"Heresy is taking a theoretical position contrary to dogma; Francis does not deny dogma in theory, but authorizes a discipline and a practice contrary to those that should normally result from the Church’s doctrine. Amoris Laetitia reaffirms the indissolubility of marriage but says that it is possible to behave toward divorced-and-remarried persons as though their attitude did not constitute a denial of indissolubility. Yes, believe in the dogma, but in practice you can behave as though the dogma were not true.
[...]
Francis says that the indissolubility of marriage is a serious duty, but he adds that adulterers must not be the object of any discrimination. That amounts to forbidding adultery in theory and allowing it in practice. The document would be heretical if it allowed adultery in theory. If it forbids it in theory, it is not heretical. But since it allows it in practice, we must say that, without being heretical, it favors heresy."

3. This issue is straightforward: there is no automatic loss of papal office from a Pope falling into heresy, either privately or publicly.

4. Regarding this issue there are two positions within traditional Catholicism. One is that proposed by John Salza & Robert Siscoe in their site and in this article in The Remnant. The other is that arrived to by Fr. Gleize as conclusion of his study of the issue, thus summarized in the interview:

"It is clear that the Pope is not absolutely infallible, outside of the precise conditions indicated for us by divine revelation. He can therefore be guilty of errors. Is it possible that he might go as far as heresy? And if he goes that far, does he lose the pontificate? The answer to these two questions is not simple, because it involves several findings of theology. We say that the Pope can fall into heresy, but that only Christ would have authority over him to relieve him of his office."