The word Takfiri is derived from Takfir.. from Ta-Kafir.. Ta being the loose term for referring to males in the second person. So to declare someone a Kafir. Only two people may be branded Kafir(or referred to as Takfir)...those who have openly stated they do not believe in god, or those who openly defy the laws and commandments of god as revealed to them. So, in essence.. if I was to refer to a Hindu if someone asked me what his religion is.. I could say Takfir. However, branding a Muslim as Kafir without unequivocal proof of their declaration or violation of commandments is considered a huge sin and violation of Islamic brotherhood. So those people who would regularly use this word against their fellow Muslims over the slightest disagreement in views were branded Takfiris.. i.e those that brandish the accusation of Kafir, or Shirk or Bidah without proper proof through witnesses and/or references from the Quran or Sunnah.
The Tableeghi Jamaat aren't violent, but the ideology they preach has certain interpretative ideals that many disagree with.However, being such a large movement they were ideal targets for Hijack by vested interests and essentially that is what happened. Certain sections turned violent or Takfiris(refusing to sit and pray with other Muslims over interpretative disagreements etc), other's came under the influence of foreign teachings whilst others became isolationists. Certain there are those that take inspiration from being more Arab than what is our heritage... by going all out with the Thawb, or with the Ibn and Bin Arabic nomenclature even outside of Arabic speaking environments.
Not completely.. there are many different schools of thought and various "scholars" that operative within the larger setup who are less virulent than the rest. Or rather arent a disease at all and are very proactive, progressive and charitable in their works.
They do however, fall within the overall encompass or "brand" of the Tableeghi Jamaat and hence earn their share of ire as well.