Here some definitions from various dictionaries:

sect/ from internet search definition:

1. a group of people with somewhat different religious beliefs (typically regarded as heretical) from those of a larger group to which they belong.
2. Similar:(religious) cult religious group faith community denomination persuasion religious order splinter group faction schism heretical movement
3. DEROGATORY a group that has separated from an established Church; a nonconformist Church.”two of the older sects—the Congregationalists and the Baptists—were able to increase their membership dramatically”Similar:(religious) cultreligious groupfaith communitydenominationpersuasionreligious ordersplinter groupfactionschismheretical movement
   • a philosophical or political group, especially one regarded as extreme or dangerous.

A definition from dictionary.com:

sect

^{[ sekt ]}SHOW IPASee synonyms for sect on Thesaurus.com

noun

a body of persons adhering to a particular religious faith; a religious denomination.

a group regarded as heretical or as deviating from a generally accepted religious tradition.(in the sociology of religion)

a Christian denomination characterized by insistence on strict qualifications for membership, as distinguished from the more inclusive groups called churches.

any group, party, or faction united by a specific doctrine or under a doctrinal leader.

THEREFORE:

Dictionaries say that a sect has deviated from a generally accepted religious tradition. The word sect has a derogatory sound.

The Ahmadi-Muslims belief that they follow the correct interpretation of Islam and therefore have not deviated from its original teaching.

Consequently let us avoid the word Sect and stick to the word Jamaat.

JUST MY VIEW.