"Amendment one of the Constitution of the United States guarantees to every citizen full freedom to decide whether En Kelohenu shall be babbled off or sung." So allows the writer in the American Israelite, even as he critiques the decision against singing En Kelohenu by Rabbi Avraham Gershon Lesser (1834-1924) an American Orthodox rabbi in Cincinnati, president of the Agudas Harabbonim, and active Mizrachi leader.
Attacking Orthodoxy for inconsistency in fealty to halacha was a typical and constant Reform polemic against Orthodox Judaism. Sometimes the argument would be, our people profane the Sabbath, and so do the Orthodox laymen - but only the Orthodox laymen are opposed to omitting a piyut. This was a charge constantly leveled at the types of modern or Neo-Orthodoxy which did make some compromises against the strictest possible approaches, while remaining strict about other things (e.g., head-covering).
Interestingly, here the attack is on this stringency - not to sing En Kelohenu because it may lead to... English - because in other cases, this same rabbi was lenient or permitted or ignored things blatantly against halacha. In this case, the argument is that the same synagogue presided over by a rabbi who decided against singing En Kelohenu hosts mixed dances.
He goes on to expose other inconsistencies, where Rabbi Lesser had permitted mild Reforms of the type vehemently opposed by authorities like the Chasam Sofer. And as you can see, by the sources he quotes, this particular writer was keeping very much abreast of current rabbinic scholarship, quoting rabbinic journals of the time, such as Veyelaket Yoseph of Bonyhad, Hungary where current rabbinic scholarship was constantly published.
Finally, he closes by claiming that "even the so-called strictest orthodoxy that boasts of its consistency, that invents constantly new laws on Shehitah or on Mazzot is expediency, measured by the standards of the codes and the authorities which it never tires of proclaiming as infallible guides."