This is fundamentaly a liberal conception of the world, that the solution to everything is to just have the right people in charge. The constant regeneration of capitalism is not born out of some individuals conscious will. It is ideological, structural, etc.
Conceptually you’ve jettisoned the very idea of class struggle, you’ve interalized defeat to such a degree that revolution is preemptively liquidated, and in its place put forward the same blathe utopianism that has been repudiated for hundreds of years. I will give you things though, you are correct to not tail this or that power, but by no means are you a Communist.
To think that millions of people of this world bled, toiled, and dedicated their lives under the sky of a Communist horizon, in the name of revolution, could be swept away in just a few sentences in an internet comment is not just a horror of its inadequacy to capture the experience of the world proletarian revolutions of the past, but it is pure arrogance!!
Well to give an off-the-cuff answer its not a matter of ‘accepting’ everyone into the Party, but rather that the Party is an expression of class-consciousness, which coupled with the vanguard of the proletariat in a leading & organized position is able to organize the revolution from the level of a strategist. Through an organic chain of links it is able to generate organizations for the middle-strata of the proletariat. Crucially, the Party maintains a mediated relationship with the masses. To accept everyone into the Party is to lose the necessary strategic element of revolution, prostrating itself to spontaneity, subordinating ideology to politics. It is, in a word, opportunism.