Paul was accused of not being "loving" because he had to stand so hard against those beliefs and people who were not in the truth. He had to ask, "Have I become your enemy because I've told you the truth?"
He was persecuted more than any man, because Christ gave him the commission to establish true-truth in all the churches. He was hated for it. At times he had to get quite rough with his words.
Paul's love was the most self-sacrificial love of all. He wasn't out to win a popularity contest or to impress anyone but his Master.
Paul is the man who defined real-love by his life, actions and words.
Mark fled from Paul at one point because Paul blinded a man by His power.
Much confusion about Paul's and even Jesus' behavior that we don't see as Loving - though they wrote 1 Corth 13 - but there should be no confusion - because Paul loved His Truth above all else, because without His truth, the Church would/will fall and Paul knew that and took great costs to himself to fight the good fight, and warns us of the things we must deal, within our own generation. That is love.
Jesus' Love cleared the temple and spoke frankly to the religious heads of His day. If that isn't love, I fear what else that we'd prefer it to be, that isn't from the 'whole' counsel of GOD within His Word.
2Ti 3:1 This know also, that in the last days perilous times shall come.
2Ti 3:2 For men shall be lovers of their own selves, covetous, boasters, proud, blasphemers, disobedient to parents, unthankful, unholy,
2Ti 3:3 Without natural affection, trucebreakers, false accusers, incontinent, fierce, despisers of those that are good,
2Ti 3:4 Traitors, heady, highminded, lovers of pleasures more than lovers of God;
2Ti 3:5 Having a form of godliness, but denying the power thereof: from such turn away.
2Ti 3:6 For of this sort are they which creep into houses, and lead captive silly women laden with sins, led away with divers lusts,
2Ti 3:7 Ever learning, and never able to come to the knowledge of the truth.
2Ti 3:8 Now as Jannes and Jambres withstood Moses, so do these also resist the truth: men of corrupt minds, reprobate concerning the faith.
2Ti 3:9 But they shall proceed no further: for their folly shall be manifest unto all men, as theirs also was.
2Ti 3:10 But thou hast fully known my doctrine, manner of life, purpose, faith, longsuffering, charity, patience,
2Ti 3:11 Persecutions, afflictions, which came unto me at Antioch, at Iconium, at Lystra; what persecutions I endured: but out of them all the Lord delivered me.
2Ti 3:12 Yea, and all that will live godly in Christ Jesus shall suffer persecution.
2Ti 3:13 But evil men and seducers shall wax worse and worse, deceiving, and being deceived.
2Ti 3:14 But continue thou in the things which thou hast learned and hast been assured of, knowing of whom thou hast learned them;
2Ti 3:15 And that from a child thou hast known the holy scriptures, which are able to make thee wise unto salvation through faith which is in Christ Jesus.
2Ti 3:16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
2Ti 3:17 That the man of God may be perfect, throughly furnished unto all good works.
1Ti 4:16 Take heed unto thyself, and unto the doctrine; continue in them: for in doing this thou shalt both save thyself, and them that hear thee.
Each member/part of His Body has a different function, but He is The Head - The Truth, The Life and The Way - Glory to HIM Alone, The WORD of GOD.