why does the financial statement called 'a general purpose' statement?

Answer 1

I presume you're referring to the "normal" financial statements prepared under generally accepted accounting principles (GAAP) with no specific instructions from anyone with special interests. Financial reports prepared under GAAP are intended to be general purpose in orientation. This means they are not prepared especially for owners, or creditors, or any other particular user group. Instead, they are intended to be equally useful for all user groups. General purpose financial statements are intended to meet the needs of users who are not in a position to demand reports tailored to meet their particular information need. As such, attempts are made to keep them free from bias (i.e. they are neutral).

In contrast, business managers, for e.g., may ask for specialized reports, budgets, product costing data, and other details that are generally not found in the "normal" financial statements for business planning, controlling, and decision making purposes.

Answer 2

it is for a non-specific prupose