tefilla - Why do we pray for G-d to smash down our fellow Jews?

My question refers to the twelfth blessing of the Amida, which seems to contravene the Biblical mitzva of ahavas yisroel*:

"And for the slanderers let there be no hope; and may all wickedness perish in an instant; and may Your enemies be cut down speedily. The wanton sinners -- may You speedily uproot, smash, cast down, and humble speedily in our days. Blessed are You, HaShem, Who breaks enemies and humbles wanton sinners."

According to my siddur (Artscroll), this originally referred to "heretical Jewish sects" such as the Sadducees, and also refers to heretical influences today. I may not know my history, but to me, the Sadducees seem no "worse" than karaites; and in any case, does it really matter? We are supposed to love our fellow Jews regardless of their faults, perceived bad influences, and differences with our opinion, then and now, no?

So how does praying directly to G-d to have them "broken," "smashed," "cast down," "cut down," etc., fit together with this essential concept?

(*Relevant mitzvot and sources: #26, and possibly #34, on the list here.)

Answer

A medrash Tehillim on perek 118 cites the explanation of Beruria that the verse says "yitamu chataim min ha'aretz" - not that the sinners should be destroyed, but sin should be destroyed - we do not pray for the destruction of the evildoers. The wording of this blessing echoes that sentiment - kol harisha means the evil, not the evildoers. We never pray for them to be destroyed - that is only for "oyvecha" - Your enemies. Nonetheless, we want the evildoers to cease being evildoers. If that requires them to be cast down and broken, the result is that they be humbled, which is the point of misfortune and tragedy (See R' Dessler in Michtav Me'eliyahu about 5 levels of belief). In the end of the day, it is out of love for them that we want them to fail in order that they reconsider their actions and their path.

The Maharal in Be'er HaGolah Be'er Sh'vi'i explains this beracha along these lines (see here in the R' Hartman edition, p. 419-421).

The Maharal explains how each clause of the beracha is directed towards the nature of the evildoer, but not towards the evildoer himself:

״ולמשומדים אל תהא תקוה", שלא יהיה תקוה להם שיהיו עוד המשומדים במציאות, רק יסורו מן העולם. ורצו לומר שלא יהיו עוד אנשים כאלו בעולם, רק יחזרו מן מעשיהם

"Let there be no hope for the meshumadim" - that they should not have any hope of there being meshumadim in existence, but they should depart from the world. Which means to say that there should not be any people like that in the world, just that they should turn away from their actions.

״וכל המינים כרגע יאבדו״, שלא תהיה דעת מינות בעולם, ואז יהיו נאבדים המינים מן העולם

"And all the heretics should be lost in a moment" - that there should not be any more mindset of heresy, and then the heretics will be lost from the world.

ואילו היה מתפלל ׳וכל המינים כרגע ימותו׳, היה משמע כי מתפלל על מפלתן. אבל לא אמר רק ״וכל המינים כרגע יאבדו״, היינו כי לא תהיה עוד דעת מינות בעולם

Were it that we prayed "all the heretics should die" it would imply that we pray for their downfall. But we just say "they should be lost," meaning that there should not be any more heresy in the world.

The Maharal continues line by line through the rest of the beracha with this approach.