Heresy is worse than idolatry

How many times has a Zionistic leaning person told you that the Gemara says it is better to live in Eretz Yisroel in a city mostly of idolaters than outside Eretz Yisroel in a city mostly of Jews? This is a standard Zionist propaganda line. The reference is given to push you to move to the 'medinah.' 

The Gemara is in Kesubos 110b:

ת"ר לעולם ידור אדם בא"י אפי' בעיר שרובה עובדי כוכבים ואל ידור בחו"ל ואפילו בעיר שרובה ישראל

(Steinsaltz translation, from the William Davidson edition on Sefaria:) The Sages taught: A person should always reside in Eretz Yisrael, even in a city that is mostly populated by gentiles, and he should not reside outside of Eretz Yisrael, even in a city that is mostly populated by Jews.

Response from Parsha Pearls:

The word "even" means that this is the limit, but more than that – i.e. something worse than gentile idolaters - is not permitted. Jewish heretics are worse than gentile idolaters, "for they afflict Israel and lead the people astray from following Hashem.” (Rambam, Laws of Idolatry 10:1) A person is naturally more influenced by one of his own kind. (See Vayikra, p. ??.) Furthermore, the evil inclination for idolatry was slaughtered long ago by the Men of the Great Assembly (Yuma 69b), whereas heresy remains a strong attraction (see Avodah Zarah 27b). One must distance himself more from heresy than from idolatry, as it says (Shabbos 116A): "Even if one is being pursued by a murderer or a poisonous snake, he may enter a house of idol worship but not a house of heretics, for the gentiles were never taught the truth, whereas the heretics are Jews who learned Torah and then denied it." Therefore, the Gemora in Kesubos does not mean that one should live in a city of mostly heretics.

In other words, that Gemara refers to gentile idol worshippers. What we have in Eretz Yisroel today are Jewish heretics, which is something far more dangerous. So rather than telling you to move to Eretz Yisroel in our times, this Gemara is telling you not to. 

I would add that Israeli society today isn't merely mostly heretical, the great majority, around 80% is heretical.