Quote 1
But he had an approved tolerance for others; sometimes wondering, almost with envy, at the high pressure of spirits involved in their misdeeds; and in any extremity inclined to help rather than to reprove. "I incline to Cain's heresy," he used to say quaintly: "I let my brother go to the devil in his own way." In this character, it was frequently his fortune to be the last reputable acquaintance and the last good influence in the lives of downgoing men. (1.1)
Mr. Utterson is less judgmental of bad behavior than most of his contemporaries.
Quote 2
This document had long been the lawyer's eyesore. It offended him both as a lawyer and as a lover of the sane and customary sides of life, to whom the fanciful was the immodest. And hitherto it was his ignorance of Mr. Hyde that had swelled his indignation; now, by a sudden turn, it was his knowledge. It was already bad enough when the name was but a name of which he could learn no more. It was worse when it began to be clothed upon with detestable attributes; and out of the shifting, insubstantial mists that had so long baffled his eye, there leaped up the sudden, definite presentment of a fiend. (2.1)
Mr. Utterson is very definitely disturbed by the idea that a) Dr. Jekyll would give over his fortune to some unknown person, and b) that this unknown person is supposedly evil.
Quote 3
And the lawyer set out homeward with a very heavy heart. "Poor Harry Jekyll," he thought, "my mind misgives me he is in deep waters! He was wild when he was young; a long while ago to be sure; but in the law of God, there is no statute of limitations. Ay, it must be that; the ghost of some old sin, the cancer of some concealed disgrace: punishment coming, PEDE CLAUDO, years after memory has forgotten and self-love condoned the fault." And the lawyer, scared by the thought, brooded awhile on his own past, groping in all the corners of memory, least by chance some Jack-in-the-Box of an old iniquity should leap to light there. His past was fairly blameless; few men could read the rolls of their life with less apprehension; yet he was humbled to the dust by the many ill things he had done, and raised up again into a sober and fearful gratitude by the many he had come so near to doing yet avoided. And then by a return on his former subject, he conceived a spark of hope. "This Master Hyde, if he were studied," thought he, "must have secrets of his own; black secrets, by the look of him; secrets compared to which poor Jekyll's worst would be like sunshine." (2.50)
Mr. Utterson’s first conclusion is not that Dr. Jekyll is evil, but that Mr. Hyde must be blackmailing Dr. Jekyll for some past sins. This conclusion is prejudiced by feelings of friendship for Jekyll.