There is a web site that contains many of Yaakov Shewekey’s video songs, which originally a link was provided to the songs mentioned above. The initial thought was that since the site didn’t contain the usual YouTube ads and the songs “Elokei Oz” and “Hamalach” are spiritually uplifting and seem to encourage a mixture between music and holiness, vilnagaon.org would provide a link. After all, the disciple of the Vilna Gaon in Kol Hator, chapter 5, section 2 says there are seven types of wisdoms needed to advance the redemption. One of them is the wisdom of music and holiness.
In the end the link was cancelled out of concern that other songs in that site might end up leading to adopting a philosophy that goes against the 7 wisdoms that the Vilna Gaon thought were necessary for the best service of Hashem.
It should be stressed different people have different backgrounds and different sensitivities and some wouldn’t be affected at all if they were exposed to those other songs.
Nevertheless, since it is not clear to the management what results would be obtained by the link, the link was removed.
Appendix: It is more likely that those who accept the 7 wisdoms philosophy of the Vilna Gaon also support the renewal of the commandment of Tekhelet. It is not an absolute connection, just one of several factors. Below this paragraph, a short musical video on Tekhelet is provided.