Tiktok originates from China and since there's a tension between this two big countries, people in India are doing their best to boycott all the possible Chinese products and even the technology, well I also heard that Tiktok will leave Hongkong as well.
Basically the other apps was have that too that not coming from china but i agree too, For This case china was the number one and that was really bad, For Doge Challenge looks like it's just some short hype and not really sure if this trend will continue but even like it was good news for the crypto community since it will introduce cryptocurrency to normal people.