What is the ruling on one who says that whoever harms his brother in Islam is an infidel, based on the hadith: "None of you truly believes until he loves for his brother what he loves for himself," and is this considered an apostasy?

"Speaking about Allah without knowledge is among the gravest and most sinful prohibitions, for it entails lying about Allah, attributing to Him what is not befitting, and altering the religion. It is the root of polytheism, disbelief, and innovations, and its danger escalates when it involves excommunicating Muslims. A severe warning has been issued against anyone who excommunicates a Muslim, stating that 'the disbelief returns upon its speaker.' The intent behind this is to emphasize and strongly deter the excommunication of Muslims, not that whoever excommunicates a Muslim thereby becomes a major disbeliever (kafir akbar) expelled from the faith. Rather, the sin of excommunication returns upon him."