Is casting aspersion to a man (who has more than one wife or who intends to marry another wife in addition to the existing one or ones, as the case may be) is justifiable from religious point of view?

Allah says in the Quran:
"Have no fear of people; fear Me, and do not sell My revelations for a petty price: those who do not judge by the law which Allah has revealed, are indeed kafirs (unbelievers)................... those who do not judge by the law which Allah has revealed, they are the wrongdoers." [5:44-45] ".......... those who do not judge by the Law which Allah has revealed, they are the transgressors.[5:47]

What do you mean by "casting aspersion to a man"?

Aspersion here means: a damaging or derogatory remark or a slander; the act of defaming or slandering.

I dont think it is nice for us Muslims to do that. If it was acceptable, then ALLAH subhallah wah tallah would have stated in the Quran to do so. Instead of commanding us to be kind and just to them. ALLAH is the judge, we arent. We are no state to commit kufr with our tongue, by slandering other Muslim

ALLAH knows best.

My point is that polygyny is permitted by Allah, while there are many among us who slander it as well as the men doing it. What will you call them, the slanderers, in the light of the Quranic verses of 44, 45 and 47 of Surah Al-Mayeda ?

I would call them hypocrites. I would say, "Listen, you have no right to voice your idiotic opinions in regards to my lifestyle when you obviously fail to adhere to all the laws of Islam".

You have raised two points:
One, some people marry two or more wives even if they are unable to maintain them all. It seems you are inclined to accuse for this the plural marriage law ordained by Allah for the benefit of His slaves. But a man cannot marry a woman at his sweet will; it requires mutual consent. If a man and one or more women tie themselves in marriage, why should it be others' headache? Besides, Allah has ordained in the Quran for those men who are unable to maintain a wife to exercise patience until He gives them the ability to maintain a family. Again the definition of maintenance is a matter which is different to different people. However, if a man marries a woman concealing his inability to maintain her and thereby afflicts her, it will be, in my opinion, a personal fault of that vey person like the fault of those engaged in adultery, bribery, dacoity, usury, theft, lying and so on.

Two, as regards spending time equally between the wives, I believe it is an invention of some misconceived scholars; for it is practically impossible for a man to share time equally. Besides, Allah wants ease for His slaves and He says:"It is not possible for you to treat equally between your wives even if you wish to do so; therefore, in order to comply with Divine Law, do not lean towards one wife to the extent that you leave the other hanging in air. If you work out a friendly understanding and fear Allah, Allah is Forgiving, Merciful."[4:129]

This signifies that there may be discrimination between the wives; but the degree of discrimination should not be so great as to do everything for one and neglect another altogether, that is, one should love and maintain his all wives and spent time with them, as is ordinarily desired for a husband, though at varying degrees.

Alas, I've seen even more serious abuses of polgyny, and some wonderful examples of where it's worked beautifully. If the man lives in the West, his wives may not have equal status under local law, which causes problem if a man dies without a will or is hospitalized, in acrimonious divorce cases, etc. If the man's wives live in seperate countries, then the man's ability to treat them equally can be compromised by travel time, immigration issues, local laws, etc. If they all live in a country that recognizes plural marriage, abuses sometimes occur on a more personal level- threat of plural marriage can be a form of abuse. Plural marriage, just like monogamous marriage, can be used well, or poorly. It does depend upon the individuals involved, and the willingness to work out a mutually agreeable way of life. As far as insulting a man simply for having more than one wife (assuming no injustice or ill-treatment), why not insult the man's hairstyle, or bad breath? It holds more opportunities for friendly ribbing, and is ultimately just as pointless.

Fabulous comments...It looks like people could just learn to mind their own business. What purpose do insults hold?

Could you elaborate your sayings?

CASTING ASPERSION T0 POLYGYNY is an act of agression in that Allah says: "O you who believe, do not prohibit good things that are made lawful by God, and do not aggress; God dislikes the aggressors." [5:87]

wow... another topic of this...

do u practice polygyny?

Is polygyny is a profession to be practised ?
Polygyny is a divinely ordained system of marriage; and speaking the truth is a believer's paramount duty. It is obligatory for believers to tell others to do good things and shun bad ones. Slandering polygyny or a polygenous man is surely a bad thing and such slander goes against Allah.