I regard Buddhism as simply a philosophy which contains (as it happens) a great deal of truth.
I fully agree that Buddha was a great and holy man, and a profound philosopher who rightly say the problem of suffering as one of the greatest problems confronting humanity.
However, I am a Christian because I believe that certain Buddhist teachings are simply in error; and other Buddhist teachings contain a glimmering of the truth, but also elements of error.
Christians who 'put down Buddhism' as simply 'demonic' are misinformed; and in any case, I would agree that they have taken the wrong towards engaging informed Buddhists in dialogue.
To make clear what some of the problems inherent in Buddhist philosophy amount to, I am going to critique some of the points you have made.
I hope that by doing so, you will see why I choose to be a Christian as well as some of the various points on which I regard Buddhist teaching to be in error.
Here is my critique:
1) 'He said - knowledge seekers like us from the university should not resort to such uncivilised ways of preaching.'
Response: Is your master implying that 'knowledge seekers' like yourself (whom he identifies with the students at a university) ought alone to abstain from such 'uncivilised ways of preaching'? Is he suggesting that it would be beneath you to have recourse to such 'ways of preaching'?
Does he not know that by appealing to your pride to keep your instincts in check, he is actually bringing about a situation wherein you will seem to yourself to be virtuous because of your success at keeping your instincts in check, even though you will in fact be a very proud person?
Does your master not regard pride as a sin?
2) 'From then on, he researched into all the teachings of Buddhism and found that it is flawless and was the teaching that he wanted to bring to the people. Being repentant of his earlier action, he renounced as a monk.'
Response:
If your master found Buddhist teachings flawless, then that must be because he had found the teachings of other faiths to be flawed; and if he then wanted to bring the message of Buddhism to the people, then it had to have been the case that he was fully aware of the fact that by disseminating Buddhism in this way, he would necessarily have been forced to imply to his audiences, that the messages preached by the other faiths were all flawed.
This being the case, your master too is engaged in the act of criticising (albeit not overtly and in an uncivilised fashion) the messages preached by other faiths.
Moreover, if your master felt that it was necessary for him to become a Buddhist in order to repent of his earlier action, then it is obvious that he has not fully understood Christianity; for on any sound view of Christianity, it would be simply wrong that one should communicate the message of Christianity to a Buddhist by the method of persuading him that his faith as a Buddhist is in every sense demonic.
3) 'So, people who want to put down other people religions must in the first place go and learn more about it - otherwise it will be hated by others. Which is why Christians also receive quite many 'bashings'. This is karma, they bash ppl, ppl bash them

'
Response:
If it's 'karma' that a person is 'getting bashed' because he 'bashed' someone then it has to follow that whoever he bashed must himself have deserved the bashing he received; otherwise, it would seem impossible for the latter person to have been able to be bashed in the first place.
But if this is so, then why cannot I take the view that I should be entirely justified in doing something which is evil, so long as I would be prepared to reap the consequences for doing it?
On this view of the matter, we do not even need to consider whether or not such 'bashing' is morally correct in the first place (whether there is any sense in which it could ultimately be said to be moral); for so long as we feel that the operation of 'karma' will ensure that whatever evil we do will come to affect only those persons who could deservingly be made subject to its sway, we need not even be bound to feel that the evil which we do is in fact evil, except from a certain subjective point of view.
That is why many Buddhists regard morality as subjective; and that is one of the reasons why I am not a Buddhist.
Ben