There is nothing extreme about kissing my partner. Straight people kiss all the time.
What is extreme is hatred, what is extreme is hiding who I am or toning myself down for the sake of my oppressor's comfort.
It is very difficult to know whether a demonstration feels "extreme," especially across cultural lines, and without being present to feel the spirit of the group. I know that some demonstrations outside Catholic churches & facilities feel really negative, because the protesters clearly hold the church, or religion in general, in contempt. The protest needs to balance outrage at the hierarchy' actions with respect for religious beliefs and for sacred space. Also, it is important to respect the beliefs and feelings of Catholic LGBT people, including those who are conservative in their religious faith and expression.
There is the problem of translation as well. Does the word translated "faggot" convey the same connotations in the original language as the word conveys in English? How do we know that?
I think a kiss-in outside a Catholic church is somewhat like a flag-burning outside a nuclear weapons plant. The literal action is so offensive to one's opponents that they cannot perceive its symbolic meaning, or be persuaded by it. Even if the action was intended in a spirit of love, it is difficult to imagine that it could be received in that way. We are more likely to achieve lgbt rights by helping Catholic faithful to see our humanity, than by insulting, or being perceived as insulting, their beliefs, values, symbols and sacred space. This approach is already working in the United States. Let Catholics lead the protest using symbols affirming of their Catholicism.
There is a benefit to actions that have shock value, especially in response to violence or repression. What is important is to be in control of the symbols one is using, so far as possible, so that they communicate what you want to say, and are likely to get a positive response from one's opponents, or at least from the general public. Chaining oneself to a church door or otherwise nonviolently blocking access to a place from which we have been denied access as lgbt people, while not violating that sacred space, seems a more controlled and persuasive symbolic action than a kiss-in or public nudity. Performing such an action as an act of prayer or solidarity would be best.
Extreme tactics ALWAYS risk alienating some people, and ALWAYS raise the awareness of some others. The number of people alienated vs. educated is the key factor in deciding whether to use extreme tactics.
While I don't approve of vile name calling, I believe that calling a bigot a bigot is just telling it like it is. I think the clergy in this case were vile using the 'f' word. I think sometimes, especially if you are the minority and don't have money and access to the media UNLESS you do something extreme, that, sometimes, extremism is absolutely necessary to wake people up!
The older I get, the less I feel the need to scream and holler and the more I just wish folks could just try harder to see Jesus in EVERYONE! That was as much of a shout as I care to make on this comment.