All religions base their doctrines on what adherants agree and believe are true conditions, and those conditions change with time. Some people do not like change, and many of them will stay with the religion but switch to another denomination. But change is frequently necessary, othrewise the religion (or denomination) dies.
Here are a few examples of significant changes to doctrines and practices.
Animal sacrifice is forbidden but in the past it was an important part of Hindu life, as described in texts such as the Vedas and the Mahabharata.
Mahatma Gandhi was a notable visionary and updater of Hindu thought by, for example, ending untouchability. He was assassinated for his views by a fellow Hindu, who couldn't accept Gandhi's radical ideas such as cooperation with Muslims.
Even though death penalty is frequently commanded in the Hebrew Bible, Rabbinic Judaism abolished it. Also moving with the times, "an eye for an eye and a tooth for a tooth" (Exod. 21:24) was no longer equivalent retaliation, rather the victim could choose financial or some other form of compensation.
The command of Jesus to turn the other cheek (Matt. 5:38-42; Luke 6:27-31) is seen as putting "an eye for an eye and a tooth for a tooth" into its correct context, that of not justifying personal vengeance.
More and more, Jewish people participate in the cultural practices of the local Gentile (not Hebrew) population in a way that would have been unthinkable in Biblical times. Enlightened Jews have allowed secular education to run parallel with Jewish education.
In the past, Catholic priests were not required to be celibate and most rural priests were married. The Church changed all this the 12th century which upset many Christians. In the 21st century the issue is being revisited, which is upsetting many Christians.
In the past, no Christian churches married gay couples. Literal reading of the Scriptures can easily be found to support the ban of same-sex relationships, but the central message is that love, true love, can and must be shared by all. In the 21st century the issue is being revisited, which is upsetting many Christians.
Some parts of the Bible seem quite absurd today. Take for example the geocentricism of Eccles. 1:4-5 "The sun also rises, and the sun goes down and hurries to the place from which it came." During the various Inquisitions, those who embraced scientific ideas of Copernicus, Galileo or Newton to be guilty of heresy.
The Church now accepts that the Earth is not the centre of the universe – in 1992 Pope John Paul II formally exonerated Galileo for saying just that. The Church continues to struggle with doctrine, which appears at odds with the new truths that God is revealing through science.
Depicting the Prophet Muhammad is forbidden but in the past his images were part of Ottoman and Persian art. There was no electricity in 7th century and until relatively recently, electronic devices such as radios, television, telephones, and even loudspeakers were haraam. Without using such technology today, society, including Islam, could not survive.
The ulama (legal scholars of Islamic or Sharia law) are tasked with considering and reassessing writings relating the beliefs and practices of Muhammad. As late as the 1970s birth control was haraam in Iran, unlike today where even pre-marital family planning lessons are promoted and there is state-support for condom manufacturers.
So Islam has changed, but the changes have not been universal. Different countries and regions have different cultures, all of which differ from Arabia in the 7th century. And as recent events have shown, such changes are violently opposed by a small minority of Muslims.
In the past, Mormons battled with the US Congress over the Mormon custom of polygamy. The church said it was their religious conviction; the government said it was illegal.
According to the then church president, Wilford Woodruff, Jesus Christ intervened by appearing to him in a vision with instructions to cease the practice of plural marriage. This was not seen as bowing to government pressure, but as an inspired change of theological beliefs. It was, needless to say, upsetting for the membership.
In addition to changing the prohibition of surfing the internet, Jehovah's Witnesses changed their symbol from a cross to a stake. It was their way of showing how they are different from mainstream Christianity, changing history by diluting the suffering of Jesus on the cross.
Scriptures can guide us and religious leaders can guide us. But as to what and whom we believe is for us to decide. If we believe in something because we have been told to believe it, then we must accept we have been sucked into a cult.