You should explicitly send it to youtube. You can do this by specifing the package:
intent.setComponent(new ComponentName("com.google.android.youtube","com.google.android.youtube.PlayerActivity"));
Also note that you should also check if youtube is installed!
Intent intent = new Intent(
Intent.ACTION_VIEW ,
Uri.parse("https://www.youtube.com/channel/UCRmoG8dTnv0B7y9uoocikLw"));
intent.setComponent(new ComponentName("com.google.android.youtube","com.google.android.youtube.PlayerActivity"));
PackageManager manager = context.getPackageManager();
List<ResolveInfo> infos = manager.queryIntentActivities(intent, 0);
if (infos.size() > 0) {
context.startActivity(intent);
}else{
//No Application can handle your intent
}