Assalamu alaykum. I read that praising the religion of the disbelievers is disbelief. What does that mean exactly? Are the following statements included in that:1. "The idea of democracy/communism is good by itself." (Meaning if you would view this matter irrespective of islam, but because it contradicts islam, you reject it.) 2. "Judaism is a good religion." (Because of the similiarities to islam, not judaism in an absolute sense.) 3. Speaking good about a law that contradicts islam, but you only mean the idea behind that or the good intention by itself. (For example: some disbelievers kill alcoholics in order to prevent corruption of society, or they completely forbid women to work to their women safe, or they kill cowards in wartime and you like only the point that they do not accept cowards, but you acknowledge that these laws are false.) 4. If you praise some groups of disbelievers because they care about their women, they are steadfast in their religion, or they are good fighters in war, but you do not mean that in an absolute way, rather, you mean some points of their behaviour.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.

First of all, it would be good to mention a general principle without going into the details of each example that you mentioned in the question; we say: the statement that praising the religion of the non-Muslims is disbelief is true because this means being satisfied and content with it, and being content with disbelief is disbelief.

Al-Buhooti, a Hanbali scholar,  quoted the following statement of Shaykh Ibn Taymiyyah in his book Kash-shaaf Al-Qinaa’:

“Whoever believes that the churches are the houses of Allaah, that Allaah is worshiped in them, and that what the Jews and Christians do is worship to Allaah and obedience to Him and to His Messenger, or whoever likes that [what they are doing] or is pleased with it, is a disbeliever as this involves the belief that their religion is true, and this is an act of disbelief, as we have previously mentioned. Or if he helped them in opening their churches and in establishing their religion, and he believes that this is an act that gets a person closer to Allaah or that it is an act of obedience, then he is a non-Muslim as this involves believing that their religion is true.”

As for the one who praises what is stated in any religion or system from what is consistent with what is stated in the true religion, Islam or, rather, what does not conflict with Islam from what is included in matters of customs, then such praise is permissible because religions agree in regard to some matters and differ in regard to some other matters. Indeed, Islam approved some of what was stated in the Torah and the Gospel and abrogated some of it. Allaah says (what means): {And We have revealed to you [O Muhammad] the Book in truth, confirming that which preceded it of the Scripture and as a criterion over it. So judge between them by what Allaah has revealed and do not follow their inclinations away from what has come to you of the truth. To each of you We prescribed a law and a method…} [Quran 5:48]

At-Taahir ibn 'Aashoor said about the interpretation of the above verse in At-Tahreer wat-Tanweer:

“The verse referred to the two cases of the Quran in relation to the previous books; it approves and ratifies some of the laws or rulings whose benefit is general, and this benefit did not change by the change of nations and times, so with this description, it certifies it, i.e. it confirms it and approves of it. The Quran, on the othe hand, invalidated some of the laws of the previous legislations and abrogated many rulings whose interests are partial and temporary considering the conditions of some specific people.”

Indeed, the Prophet praised the alliance of Al-Fudhool, which took place in  the Jaahiliyyah (pre-Islamic era of ignorance) as he said, “I had witnessed in the house of 'Abdullaah ibn Jud'aan an alliance that is for me better than the best of the camels that the Arabs possess, and if I were called to it after Islam (because this alliance took place before Islam), then I would have accepted it.” [Al-Bayhaqi]

Al-Qutaybi said, “The cause for this alliance was that Quraysh were wronging each other in the sacred precincts of Makkah, so ‘Abdullah ibn Jud'aan and Az-Zubayr ibn Abdul-Muttalib called them to an alliance; that they would support the oppressed against the oppressor…”

Allaah Knows best.