Chazal tell us that the Emorites hid their wealth in the walls of their homes. Therefore, Hashem would place tzaraas in the homes of the Jewish nation living in Eretz Yisrael. According to halachah, they had to break open the walls where there was tzaraas to cut the tzaraas out of the home. By doing so, they discovered the treasures that were hidden years before, and they became wealthy.
The Shevet HaLevi asks why this is called a נגע, a plague? This tzaraas was for his benefit! But the answer is, if a Jewish home has to be broken, it is a נגע, a plague. Along this theme, we add that those who break their homes for the sake of parnassah – they bring the internet into their homes for parnassah – this isn't a benefit; it is a נגע, a plague.
Reb Elchanan Wasserman zt'l hy'd had a yeshiva, Ohel Torah. The father of one of the bachurim wanted to take his son out of the yeshiva. He told Reb Elchanan Wasserman that (Avos 2:2) אֶרֶץ דֶּרֶ ךְ עִם ת ּוֹרָה תַלְמוּד יָפֶה, "Torah is nice when it goes together with working for parnassah." So, he wanted his son to begin working. Reb Elchanan told him that he could have brought an even better source, for it states in this same Mishnah, וְכָל עָוֹן וְגוֹרֶרֶת בְּטֵלָה ּסוֹפָה מְל ָאכָה ּעִמָּה שֶׁא ֵין ת ּוֹרָה, "Torah that doesn't come along with work, in the end he won't be able to continue learning and it leads to sin."
However, Reb Elchanan explained that there is a halachah regarding bris milah, that if the child's brothers died when they had bris milah, the child doesn't receive milah. The great mitzvah of milah isn't performed because it is dangerous to give a bris milah to this child. A father who performs a bris milah regardless would be considered a רוצח, murderer, and not that he performed a mitzvah. So, although you have a good point, that Torah should go together with working for parnassah, but what about all the brothers from Bnei Yisrael who died spiritually when they followed this path? Therefore, just as the bris milah is נדחה, pushed off when there is a danger, so, too, the pursuit for parnassah is נדחה, pushed off in the face of danger.
For our purposes, when one claims that the internet is needed for parnassah, one should remember how many of our brothers have "died" (in a spiritual sense) due to this approach. And then it will be good for them, in this world and in the next.
The first foundation for hatzlachah with children is that the house should be safeguarded and closed off from all bad things. Even if it is hard to detach from them, r'l, or he thinks that he needs them very much. He should open his heart and have rachmanus on his children that they shouldn't fall into evilness, and close the internet.
