Kevin,

It does matter, and it is understandable.

When multiple people are teaching something very different, most, if not all, are teaching something wrong.

It does matter when some people teach different things.

It happened in the 1st century:

Acts 15:1 ¶ And certain men which came down from Judaea taught the brethren, and said, Except ye be circumcised after the manner of Moses, ye cannot be saved.

 2 When therefore Paul and Barnabas had no small dissension and disputation with them, they determined that Paul and Barnabas, and certain other of them, should go up to Jerusalem unto the apostles and elders about this question.

 5 But there rose up certain of the sect of the Pharisees which believed, saying, That it was needful to circumcise them, and to command them to keep the law of Moses.

 6 ¶ And the apostles and elders came together for to consider of this matter.

 7 And when there had been much disputing, Peter rose up, and said unto them, Men and brethren, ye know how that a good while ago God made choice among us, that the Gentiles by my mouth should hear the word of the gospel, and believe.

Paul & Barnabas had "no small dissension and disputation" with those that taught differently.

Then when the apostles & elders came together to consider the matter, there was "much disputing".

Galatians 2:11 ¶ But when Peter was come to Antioch, I withstood him to the face, because he was to be blamed.

Paul had a strong disagreement with Peter.

Acts 15:39 And the contention was so sharp between them, that they departed asunder one from the other: and so Barnabas took Mark, and sailed unto Cyprus;

 40 And Paul chose Silas, and departed, being recommended by the brethren unto the grace of God.

 

Paul and Barnabas had sharp contention over the matter of Mark.

II Thessalonians 2:2 That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand.

Paul needed to warn the Thessalonians about those who were attempting to deceive them that the day of Christ was at hand.

II Timothy 2:18 Who concerning the truth have erred, saying that the resurrection is past already; and overthrow the faith of some.

Paul warned Timothy about those who saying that the resurrection was past already.

Acts 23:6 But when Paul perceived that the one part were Sadducees, and the other Pharisees, he cried out in the council, Men and brethren, I am a Pharisee, the son of a Pharisee: of the hope and resurrection of the dead I am called in question.

 7 And when he had so said, there arose a dissension between the Pharisees and the Sadducees: and the multitude was divided.

 8 For the Sadducees say that there is no resurrection, neither angel, nor spirit: but the Pharisees confess both.

 9 And there arose a great cry: and the scribes that were of the Pharisees’ part arose, and strove, saying, We find no evil in this man: but if a spirit or an angel hath spoken to him, let us not fight against God.

 10 And when there arose a great dissension, the chief captain, fearing lest Paul should have been pulled in pieces of them, commanded the soldiers to go down, and to take him by force from among them, and to bring him into the castle.

It appears that Paul purposely stirred up the contention between two groups of Jews, who believed differently regarding the resurrection.

Jude 3 Beloved, when I gave all diligence to write unto you of the common salvation, it was needful for me to write unto you, and exhort you that ye should earnestly contend for the faith which was once delivered unto the saints.

We are to earnestly contend for the faith, and that is why there are disagreements, not only about the gospel,

but about whether or not the church replaced Israel, or whether infants should be baptized or not,

or whether TV evangelists are either great healers or great charlatans, and a number of other things.

If people are teaching your brethren something wrong, then why shouldn't you be upset with them?

It does matter.