The answer to this question is complicated and there is much confusion about it given the fact that Muslim countries are under the British occupation. Therefore, it depends on who you’re asking, who is talking, and from what angle they’re coming from, but the dominator in all answers is unclarity and confusion because clarity and order is not in the interest of the oppressor.
A Muslim scholar might consider politics the public complaints of people against a Muslim leader, typically in Saudi Arabia, and they will use obvious religious texts to justify their stand. However, the majority of Muslims live under direct pagan governments and their oppression.
When a political commentator in the West speaks of politics, he or she means typically the participation in the political rallies, elections, political parties etc. Running for office is the best example of political activism, something which in Saudi Arabia would be considered an example par excellence of frowned upon political involvement.
When such Secularist commentators refer to Muslims themselves being involved into a political activity, such as running for office, they could refer to this as ‘political Islam.’ Even though from a legal perspective it is OK, they use the phrase ‘political Islam’ just to make it seem scary and different, as if to remind Muslims that in this domain follow the religious texts which speak about the obedience to the leader.
Personally, I’ve noticed that when the Secularists speak of political Islam they mean Islam itself, especially the most important practical aspects of it, such five daily prayers, hijab, organizing family according to the Islamic values, avoiding bank loans and any transaction which involves interest, fasting, giving donations, building mosques etc. They cannot attack openly Muslims on such issues because that would raise enormous political alarm and awareness in the community; instead, they appear as if they are concerned about the political Islam.
Therefore, the western Secularists do a good job by associating the word politics with Islam. In reality, they have no problem with the participation in their Secular politics because that’s a waste of time and harmless for their political power. The true problem arises when Muslims defend themselves, fight for their rights, their families, properties and want to practice their religion as much as possible. This is what the US Government and the British Empire don’t want.
On the other hand, if they participate in elections, scholars from Saudi Arabia will not support such an activity, which might be called as ‘political Islam.’ So, the vicious western politicians try to use a religious stand of the scholars of Saudi Arabia, and extrapolate that to mean the practice of religion itself by appearing that they are concerned about something that they are not, and meaning in reality what Muslims have a legal right to do: the practice of religion.