This topic has already been discussed many times.
irl there are no restrictions on the launch speed; the installation, like on other equipment, is opened manually. the only reason why the irl do not use ATMG at full speed is because the TOW is controlled by wire and they can break because of this, or leave the ATMG guidance zone due to the terrain.
And there shouldn’t be any gaming restrictions, since in fact they are artificial and made for unknown reasons.