The kingdom of heaven is like to an householder, who went out early in the morning to hire labourers into his vineyard.  And having agreed with the labourers for a penny a day, he sent them into his vineyard.  And going out about the third hour, he saw others standing in the market place idle.  And he said to them: Go you also into my vineyard, and I will give you what shall be just.  And they went their way. And again he went out about the sixth and the ninth hour, and did in like manner.
 But about the eleventh hour he went out and found others standing, and he saith to them: Why stand you here all the day idle?  They say to him: Because no man hath hired us. He saith to them: Go you also into my vineyard.  And when evening was come, the lord of the vineyard saith to his steward: Call the labourers and pay them their hire, beginning from the last even to the first.  When therefore they were come, that came about the eleventh hour, they received every man a penny.  But when the first also came, they thought that they should receive more: and they also received every man a penny.
 And receiving it they murmured against the master of the house,  Saying: These last have worked but one hour, and thou hast made them equal to us, that have borne the burden of the day and the heats. But he answering said to one of them: Friend, I do thee no wrong: didst thou not agree with me for a penny?  Take what is thine, and go thy way: I will also give to this last even as to thee.  Or, is it not lawful for me to do what I will? is thy eye evil, because I am good?
Douay-Rheims Bible: Matt 20: 1-15
The rest of the story:
The murmuring labourers continued to complain among themselves. They appealed to the procurator of their district telling him they would support him against the householder and all the others of his class if he would support them as they organized against their employer. Thus they formed a union and supported by the governor brought the vineyard owner to their table and extorted from him higher wages and shorter hours with the threat ruining his vineyard. Further, they required each labourer to support them with portions of their wages regardless of their will in the matter. Again, extortion was used, no dues, no work. Over time, the vineyards became smaller and fewer.
The parable of the vineyard owner was given to us by our Lord Jesus Christ. He uses it to describe the kingdom of heaven. What is important to understand is, Jesus used an earthly analogy to describe an eternal truth. Though He was talking about heaven, He used a moral earthly truth to illustrate His point. Jesus would never use an erroneous example to describe a truth. In other words, the vineyard owner was in the right and for those laborers to coerce from him more than he was willing to pay is a wrong. God will account for it at the judgment. The same goes for the workers who would rather not associate with unions. If they are forced to contribute, against their will, God will keep the proper account. One of the sins crying to heaven for vengeance is defrauding a laborer of his wages.