There's an article by a Christian that deals with the issue of self-defense that kindasorta addresses your question, if in a tangential way. I'll quote some salient bits:

First of all, contrary to some people's ideas, Christianity is NOT a pacifistic religion but rather one that teaches that if at all possible you should live at peace with others. ("If it is possible, so far as it depends on you, live peaceably with all."--Romans 12:18.) In verse 19 of that chapter the passage goes on to tell us not to take revenge which is retribution after the fact, but it does not prohibit self protection at the time evil strikes. In Romans 12:20 we are told to try to prevent evil by kindness ("...if your enemies are hungry, feed them; if they are thirsty, give them something to drink; for by doing this you will heap burning coals on their heads.") Yet even this passage gives no prohibition against preventing or stopping a lethal attack.

Yes, we are to do good. Yes, we are to avoid evil things. Yes, we are to treat others as we would want them to treat us by showing love, compassion, forgiveness, and tolerance to all. However, no where are we told to do nothing when confronted with an evil attack which would bring harm to ourselves or others.
[...]
People also often misquote the passage from Matthew 5:38-41 (and also Luke 6:29), "You have heard that it was said, 'An eye for an eye and a tooth for a tooth. But I say to you, Do not resist an evildoer. But if anyone strikes you on the right cheek, turn the other also; and if anyone wants to sue you and take your coat, give your cloak as well; and if anyone forces you to go one mile, go also the second mile." If this passage in fact proscribed any form of resistance to any form of attack, the logical conclusion would be that if someone attacked and raped your wife that you would then have to offer the attacker your daughter. Absurd, isn't it?

The main key to this passage is in the phrase "strikes you on the cheek" which is used instead of "strikes you." In biblical times the phrase "strike the cheek" referred to a verbal insult, and not a physical attack. In those days, (as in some modern cultures) a verbal insult was frequently responded to with a violent response especially if it dealt with one's family or parents. What is being taught here is that we are not to respond to mere words with violence.

An additional guideline is offered in the part about our "coat being taken" and going the extra mile. It was the custom during the Roman occupation for a soldier to pick a person at random and force them to carry their field pack and equipment for some distance. In addition, in the process of having the equipment carried it was common for the soldier to relieve the person of their cloak and/or tunic for the soldier's comfort. By carrying it further than custom demanded one served as a witness to Christ's love for others and the presumed non violent action of theft of property does not warrant a lethal response, since property is of much less value than a life. However, no where are we told not to respond to a violent assault.

So that addresses the physical wimpiness - but what about the vocal wimpiness (or timidness)?

There are several passages that apply to this, that address dichtomies between believers, but I believe are nonetheless applicable:Romans 14:16, Titus 1:10-11. I take them to mean "do not let falsehoods go unanswered".

This is not as difficult, or as confrontational as it sounds. If you encounter someone who says something counter to what you believe, then all it takes is a simple "I don't agree." At the very least, you let them know that there is a dissenting viewpoint - perhaps they will ask you why, and give you an opportunity to explain - and at best, they will even have an open mind about it. But letting falsehoods go unanswered gives the speaker the false confidence that everybody agrees with his viewpoint, which only enforces it.

From Theodore Dalyrmple Ayn Rand, from this article:

The opportunities to speak are all around you. I suggest that you make the following experiment: Take an ideological "inventory" one week, i.e., note how many times people utter the wrong political, social, and moral notions as if these were self-evident truths, with your silent sanction. Then make it a habit to object to such remarks - not to make lengthy speeches, which are seldom appropriate, but merely to say: "I don't agree." (And be prepared to explain why, if the speaker wants to know.) This is one of the best ways to stop the spread of vicious bromides. (If the speaker is innocent, it will help him; if he is not, it will undercut his confidence the next time.) Most particularly, do not keep silent when your own ideas and values are being attacked.

Do not "proselytize" indiscriminately, i.e., do not force discussions or arguments on those who are not interested or willing to argue. It is not your job to save everyone's soul. If you do the things that are in your power, you will not feel guilty about not doing - "somehow" - the things that are not.

None of this is antithetical to being peaceful, or humble. We have been called to be peacemakers, yes, but also truth-bearers. We shouldn't let a prediliction towards "peace" (or in this case, not rocking the boat) overcome truth.

After all, plenty of times Jesus has rocked the boat, gotten the response he wanted, and brought truth - and the peace comes after.