No reason to believe this. Plenty of reason to disbelieve it.
The opposite is the case. You are basing your conclusion on one example of what Peter did not say in one particular scriptural account. Furthermore, pacifism was not the theme in that passage, so it would have been incredibly odd for the author to have included it. Lastly, it does not follow that it did not happen simply because it was not included in the text.
However, if we look at what Jesus did say, we come away with many more quotes supporting the academic conclusion that the early Jesus movement was largely pacifist in nature. Refer to Matthew 5:9 and Matthew 5:38-48. Furthermore, Jesus says to love one’s neighbor as one’s self, and when he is asked who one’s neighbor is, he replies that one’s neighbor is one’s most bitter enemy. Of course he also tells one of his apostles to put his sword away, for those who live by the sword will perish by the sword (Matthew 26:52). You might also refer to the antimilitarist sentiment in Luke 19:41-44. Jesus echoes much of the Old Testament prophets’ antimilitarist sentiments. The Old Testament and New Testament, taken holistically, are very antimilitarist and very much for nonviolent resistance.
There is also significant historical evidence that many converted Christians claimed exemption from military service for the first three hundred years and refused to resist violently. Religion historian Roland Bainton states, “The age of persecution down to the time of Constantine was the age of pacifism to the degree that during that period no Christian author to our knowledge approved of Christian participation in battle.” Tertullian even wrote, “only without the sword can the Christian wage war; for the Lord has abolished the sword.”
Kleiderer, Minaery, and Mossa note that the overwhelming evidence seems to indicate that “Jesus did not engage in violence and, indeed, preached the opposite–that one should refrain from taking vengeance, that one should not meet violence with violence or do violence to anyone that one should love one’s enemies.” Then, most early Christians took his word for it and practiced what he preached. The religion was likely not organized enough to say that all Christians were pacifists. Indeed, some were less satisfied with the pacifist approach than others. However, the evidence seems rather clear that most Christians were pacifists for the first three hundred years.
For more, I highly recommend
Just War Lasting Peace: What Christian Traditions Can Teach Us. It was written in 2005, so it is a bit dated now, but it is an invaluable take on the just war tradition in the Church, the development of the just war tradition over the centuries, and it includes an excellent preview (though it does not go as far as leading Christian scholars on this topic are going today) of where the tradition will go from here.