The statement that 'agrarian class structure has been undergoing changes due to modern forces' is largely accurate and can be critically examined by looking at how various modern forces have reshaped the traditional agrarian hierarchy in India.

Historically, India's agrarian structure was characterized by a feudal or semi-feudal system, with a clear hierarchy of landlords (zamindars, jagirdars), tenants, sharecroppers, and landless laborers, often intertwined with the caste system. Modern forces, particularly since independence, have significantly altered this structure:

1. Land Reforms: Post-independence land reforms aimed at abolishing zamindari, imposing land ceilings, and redistributing land. While imperfectly implemented, these reforms did reduce the power of large landlords and, in some regions, led to the emergence of a class of owner-cultivators, particularly from intermediate castes. This created a more diversified landholding pattern.
2. Green Revolution: The introduction of high-yielding varieties of seeds, fertilizers, and irrigation technologies in the 1960s and 70s (the Green Revolution) had a dual impact. It increased agricultural productivity and commercialization, benefiting large and medium farmers who could afford the new inputs. This led to the rise of a 'rich farmer' class. However, it also marginalized small and marginal farmers and landless laborers who could not access these resources, exacerbating inequalities and leading to increased indebtedness and distress migration.
3. Commercialization of Agriculture: The shift from subsistence farming to commercial agriculture, driven by market forces and government policies, has integrated Indian agriculture into the global economy. Farmers now produce for markets, leading to specialization, contract farming, and the entry of corporate players. This has transformed the relationship between producers and consumers, and between farmers and capital, often making small farmers vulnerable to market fluctuations.
4. Globalization and Liberalization: Economic liberalization policies since the 1990s have further exposed Indian agriculture to global competition. While some farmers have benefited from export opportunities, many have faced challenges from cheaper imports, reduced subsidies, and increased input costs. This has led to agrarian distress, farmer suicides, and a push towards diversification or exit from agriculture.
5. Urbanization and Industrialization: The growth of urban centers and non-agricultural sectors has drawn labor away from agriculture, leading to a decline in the proportion of the population dependent on farming. This has created new employment opportunities but also put pressure on land, leading to land conversion for urban and industrial use.
6. Technological Advancements: Mechanization, use of ICT, and precision farming techniques are changing labor requirements and increasing capital intensity in agriculture. This further differentiates farmers based on their access to technology and capital.

Critical Examination: While these modern forces have undoubtedly brought about changes, the transformation is not uniform or complete. Traditional hierarchies, particularly those linked to caste, still persist in many rural areas, influencing land ownership, labor relations, and access to resources. The 'new' agrarian classes often overlap with older caste divisions. Moreover, the benefits of modernization have been unevenly distributed, leading to new forms of inequality and vulnerability for certain sections of the farming community, especially small and marginal farmers and landless laborers. The agrarian crisis, characterized by indebtedness and suicides, highlights the challenges faced by a significant portion of the rural population despite or perhaps because of these modern forces. Thus, the agrarian class structure is in a state of flux, shaped by a complex interplay of traditional legacies and modern dynamics.